How does experience say that you need a complete set of coils?! If it is COPs, and not one of the other potential causes, why do them all? Misfires are NEVER that easy to diagnose! A P030x code does NOT automatically equal COPs. This seems pretty dishonest to me.
Dishonest my a-s . I have replace so many converters because of other shops just changing one coil and a month down the road another one fails. As you must know a misfire will destroyed a very very expensive converter assembly.. You have no idea what you are talking about.
Jimthecarguy - My point is that no level of experience is enough to look at a scan tool, read a P030x code, and know with certainty that you need to replace all the coils. There has to be some form of testing. Could it be COPs? Sure it could. It could also be plugs, valves issues, or several other potential reasons. A trouble code gives the symptom, not the cause. The other issue is, if a coil is actually bad, then replace it. They do not need to be replaced as a set. The excuse of ruining the new cat a month later is not reasonable ......especially if you diagnose the misfire cause and fix it, not just throw potentially unnecessary parts at it.
How do we know the catalytic converter is “positively” no good ? What are the temperature differences supposed to be between front and back ? Also, did you replace the oxygen sensors when you replaced the catalytic converters ?
do you have experience with honda and acura vehicle do you know why honda and acura cars dont support o2 sensor 1 .... but it do support 02 sensor2 evertime when i use the scan tool ???
You have excellent teaching skills and knowledge jimthecarguy! I went to college 4 years and didn't have a phd instructor with half your teaching ability! This info is exactly what I needed after having a fuel injector stick open on my 05 F150 Triton 5.4. It hydro-locked on gasoline and bent a piston rod (107,000 miles). Check engine light flashed rapidly just as you said - I was 1 minute from home. Started engine an hour later ...white smoke billowed out tail pipe and strong gasoline odor. Fixed injector - all fine except loud knock started after starter came to halt. #4 piston rod bent. Will test cat after new engine arrives this week. Attention Triton 3-valve owners - 05 models manufactured 1/1 - 12/31 have injectors prone to this failure. Replace yours today! Ford extended warranty on these engines to 10 years or 120,000 and warned dealers of catastrophic engine failure such as mine. Mine isn't covered due to time expiration, not mileage.
Thank you Jim. Great video! I have one question. Could the Oxygen Sensor just be bad & before changing the Catalytic Converter, just change the Oxygen Sensor, be a possiblity also?
To save the customer money you could’ve swapped out the coils from the other cylinders that were working. If the coils we’re bad then the problem would follow the new cylinder position, and thus , warrants a new coil. But to simply suggest new coils based on a code and then to further suggest replacing all oils that don’t even register a code is IMHO unethical.
Great Video and Thx. Quick question. For a 2009 Mustang would u recommend using the OEM Ford Y pipe/converter for replacement or would an after market ypipe be ok? Had a rattle in one converter but its stopped. I've had 2 shops recommend the Ford OEM. Thx
I got a po136 06 Chevy trailblazer I know it suggests is a downstream O2 sensor but live data says the O2 sensor is working fine comes on after about a hundred miles got to realize this vehicle's got 205,000 me and I live in Chicago. Rust belt I do live data it shows CO2 sensors working fine. I really believe it could be the catalytic converter because if you press the gas there's hesitation that it normally wouldn't have. What's your thoughts
My O2 sensors in both banks are reading arounf 750 mV continuously (at idle and at 3000 RPM as well) Also, the LTFT in both banks are almost zero, but at steady 3000 RPM, the LTFT go to -10 in both banks What does this mean?
I have a 05 BMW x3 Both bank 1 and 2 sensor 2 are reading 92 and not moving. Could this mean that they are bad? I do have p0420 and P0430 codes. Could it just be the 02 sensors?
Thanks for an easily understandable video. I enjoy Scannerdanner's videos too, but you succinctly summarized the diagnosis of a bad cat for the shade tree mechanic.
I think I have a bad catalytic converter, Because bank 2 is mimicking bank 1, But I don't have a check engine light!? Why? Maybe later? Or can it just be 02 sensor bank 2?
First of all dont change anything til you get a code that tells you something is wrong. If you have 2 banks like a V6 or V8 engine, you want to check the sensors on each bank. Example, on bank 1, compare sensor 1 to sensor 2 with the motor hot and running and hold the rpms at about 2k rpms. As long as the engine is hot enough, sensor 1 will jump up and down between 0.1 to 0.8 rapidly, and sensor 2 should be steady around, 0.5 to 0.8. If sensor 2 is also rapidly jumping like sensor 1, then the cat might be bad cause is not heating up enough to burn gases. To double check this, use a thermometer like the one in the vid to check the inlet and outlet temps of the cat. Try to point the laser at the weld seams of the outlet and inlet. I find to get a better reading that way.
Hi i just have a question. Is the inlet temperature should be higher than outlet catalytic? Or the post cat is should be higher? And what is the normal temperature for good cat?
Great video Jim. I didn't know any of that stuff. I have a Raytek, scan tool that works through my phone and a 1999 Ford E250 with 191k....need I say more...
Mine secondary O2 sensor moves reading moves around for like 2 seconds when I switch it to that reading, but levels out at like 0.075 shortly after and doesn't move that much. Does that mean it's still good?
Try putting it on the pipe and not the heat shield the heat shield will read cooler you had it on the pipe at the front but on the heat shield at the back
I don't think this is a complete diagnosis you went straight for the coilovers and just replace them all I would have did a little more research to make sure that they were bad by switching them switches cylinders with the good one to the bad one and that I would have reset the computer to see if the misfire fault code came back I think this is the proper way to higher class the professional way to do it I think this is somewhat unprofessional to just assume that the part is bad without verifying it and to replace all 6 or 8 coilovers or all 4 whatever
I think you should only replace those coilovers if you could verify that they were bad that you switch him I wouldn't have replaced them all unless you think you have a race car or something cuz you never know some of them been replaced before Summit their coilovers
My car started hesitating after i took it to get tires rotated. found out the Mechanic took air filter out and didn’t put it back in when they did a point inspection. I put a new filter in but now i get the check engine light on. Changed the oxygen sensor out erased the code. 0420. Check engine light came out again. My question. What could a missing air filter cause the engine to cause the code ? Thank you
dirty MAF sensor ... mass airflow sensor just beyond the air filter ... with no air filter there was nothing to block whatever gets drawn into the intake ... usually in the 'accordian' looking thing ... (there's a special solvent/cleaner for MAFs)
Hi Jim. Great video. Please help me with my wife's 2013 infiniti jx35, V6 engine. After getting the engine hot the cats were at around 850 degrees. The voltage readings were as follows: B1S2 - jumped between 0.070 and 0.080, B2S2 - jumped between 0.110 and 0.800, B1S1 - around 2.0v and B2S1 - around 2.2v. Can you please help me diagnose this?
I have a 2015 GMC Sierra 1500 5.3l when I pull up the part for the converters it's showing a pipe with 3 parts on it and oxygen sensor for each how do I know which one is the bad one? I'm a widow and trying to figure out the cheapest way to fix this it's my only vehicle. Plus my truck has 167,000 miles is it normal for the converters to stop up that quickly? Please help!
I'm still wondering about the catalytic converter in my Mitsubishi outlander 03 and have one more question. If I'm randomly getting an obd code which says 'catalytic converter over threshold' is it possible that the problem is with the downstream o2 sensor? This sensor periodically reads up to 0.7-0.8V like I mentioned in my previous message but sometimes the reading from that sensor jumps all the way down to 0.1V. Would you advise me to change that sensor first before I replace the catalytic converter or in your opinion is it definitely the catalytic converter that's bad? Thank you in advance. And have a good one.
@@jimthecarguyThank you for your reply. In about ten minutes after I started the vehicle I check temperature by the laser thermometer and the temperature is almost the same on the front and on the back of catalytic converter.
That's not really true that catalytic converter when we get really hot when you step on the gas when you're running it at 2 or 300 RPM to 3000 RPM that's the only time that catalytic converter will get hot and you should know that it doesn't get hot when you sit there and idle and you know that
Jim, I drove a 91 Mazda pu for years with the check engine light on and sold it and that person drove for years with light on and never any other problem. In fact, I called the dealer and he said don't worry about it. In other words, is it always critical that the check engine light be addressed?
Hi, my check engine light on today . It say catalytic converter defect . But I have change it one month ago . Anyway I erase the code and check engine light gone . So my question is will it come back again. If so how long it will take to come back. Thanks Golf 5 ( 2008 ) 1.4 patrol engine I drove with bad kat about a week but no engine light on and after I drove another week without Kat no engine light on . When I change my both Kat and drove 500km not engine light. Then I put fuel injector cleaner and drove another 150 km . And after engine light on and it says on my obd2 Kat defect
Can you check a catalytic converters with a OBD2 code reader on a vehicle that doesn’t run? Car won’t start with code P0430 but can’t check the CC bc it won’t run
Jim, could the up stream oxygen sensor be disconnected and removed, and if engine performance has returned, would that now confirm I have a stopped up cat? I have checked and confirm all else in system...everything ignition related, mass flow sensor, egr valve, throttle body, tps sensor, clean air filter...everything under hood. Good fuel pressure confirmed. Presently engine will not run over 10 to 25 miles per hour. Removed egr valve and engine now performs somewhat normal. Reinstalled Egr valve. I think if I remove upstream oxygen sensor engine will perform normal. Engine does use a little oil. This may be my problem causing stopped up cat. Your opinion on removing oxygen sensor and doing engine test drive. Your opinion on this test drive procedure. Engine is chocking up on acceleration. Your thoughts please. Thanks..Jim.
I have a Mercedes Class C 2011 W204, the O2 sensor upstream is showing 2.0 (1.6 - 2.4) Volts and the O2 sensor is showing 0.41 (0.1 -0.6). The temp upstream is bigger than the temp downstream... Is there a probleme with the upstream sensor?
I have 96 Toyota Camry LE 4 cylinder with the P0420 code. I had previously did tune up in July changed coil packs and spark plugs and had to replace the distributer cap and rotor. The vehicle will start but will run maybe 2 -3 minutes tops then shut off and will start back up for awhile . Could I have more than just my catalytic converter as an issue?
Manufacturers should change the EML light from Yellow to Red...bcos all car manuals say warning lights in Yellow is nothing to worry about hence ..low screen wash warning is yellow...Bulb failure is yellow...low fuel is Yellow..how how we suppose to take EML light serious???..especially when the car is still running smooth...you think..oh..I haven't tighten my fuel cap😥
1997 F150 4.6 - do these numbers indicate anything to you? I don’t have a scanner . . . DRIVER side Pre-CAT 494° After-CAT 534° (40° difference) After-resonator 462° PASSENGER side Pre-CAT 436° After-CAT 574° (62° difference) After-resonator 436°
I had a p0420, used thermometer and showed the Cat is good (100° hotter downstream). The upstream voltages swings between 100mv to 900mv but the downstream shows 700mv - 800mv on idle, erratic on 50 mph. No leaks after exhaust manifold. Normal power. Fuel Trims okay. Could it be Rear O2 sensor?
I’m $1400 lighter replaced the whole system yesterday new clamps new bolts 4 new sensors 🤦🏽♂️ 07 Jeep Grand Cherokee 170K oh and a week b4 discovered had a cracked radiator on the plastic neck nxt to the upper hose another $550 🤦🏽♂️ it’s like I’ve put a down payment on a new ride 🤦🏽♂️
Car sometimes after starting stays low RPM even if you floor gas pedal . I then turn off for about a minute then restart it and usually does the trick works normally . Usually works after doing it once . Lately , sometimes a few tries . About a week ago for the first time ever turn off died several times at home and very nearby ( a few blocks ) . Someone said it's probably a bad CC . Now I'm here trying to figure what to do . I'm hesistant taking to a shop because some mechs don't know what they're doing . Already paid for a throttle body with sensor replacement and that didn't fix it . And when they've tried to scan it it doesn't show any readings . And I've checked fuses
Heh, if your check engine light is flashing pull over... I just replaced a cat on a Jeep. Lady said she drove it for a year with a flashing check engine light, and now needed it fixed for state emissions testing. Random misfire and a dead O2 sensor, burned a hole clear through the cat. Had to put on the dad voice and lecture her about ignoring the light
Jimmy when you checked the o2 sensor in bank one sensor 2 it was not fluctuating the proper way. It was the cat that was the problem. If it was a o2 sensor problem what would the scanner be showing? Did say it’s the sensor and not the cat.
Thanks. I have a toyota that had bad coils and plugs. The cat is not showing a code now but the monitors are incomplete. The scan tool says the cat is hotter upstream but it may be reading the difference between the wide band A/F sensor and the o2 sensor. Ill check with the IR thermometer.
I'm trying to diagnose my catalytic converter, even though I don't have a check engine light on. The live data on my scan tool indicates that the voltage for my upstream 02 sensors fluctuate just as they are supposed to. However, my downstream O2 sensor (the one by the catalytic converter) remains flat at zero (0.0), so what does that mean in regards to the catalytic converter?
So if catalytic work properly pre catalytic converters should be lower temp that post converter? Is this good assumption if both temp reading are same or pre cat hoter than post cat then consider replacing the catalytic? Please advice
The temp test is a start but its not the correct way, because the computer is set to go off by the smallest inefficiency. So the last car i worked on had a 100° drop from like 412 to 309 but was still setting the code p0429. So I changed the cat and light never came on again.
My down stream sensor is steady numbers and upstream sensors are moving kind slow I was told. Car is bogging down. Took sensors out drove around car drive fine, so, what’s bad , o2 or cat ?
If an cat converter is bad then air does does not move through the converter. When this happens which side would be hotter? It would be the inlet side because the heat just going to build up and not get through. Common sense. Not sure why a cat would be bad if the temps are the same on inlet and outlet
Nice video Jim. Have you ever used the method of how long the oxygen is stored in the cat? This test could be used to judge the life expectancy of a cat. Take care Jim...
Was great video thanks When rear oxygen sensor mimic the front one you say catalytic converter is not doing his job which is right But by looking at pids how we know if it is completely blocked and collaps?
I don't understand why my check engine light is not lit up but I have a problem I think it's the cat converter cause I have no power esp when the engine gets hot
Po 420 means catalytic or can be o2 sensor my car was running with misfire I replace coils spark plugs pvc valve after that runs better but po 420 apear do you think cat is bad i removed cat and look normal no damages from one side because can’t see the oposite side any help is going to apreciate
From the research I was just doing, if the converter temp is lower after the cat then it’s clogged. So it appeared on your original system , the left converter was clogged and the right was emptied.
Love the vid. I'm thinking my cat is starting to go myself. No codes whatsoever on the car. But I noticed some "popping/dinging" noises while driving today, and once I parked, I smelled a decent amount of sulfur. Going to give this a whirl on my troubleshoot journey before just assuming and making an expensive guess purchase.
I noticed you had the RPMs raised up in the second test I saw the differential in the background so does that mean you were wrong with the Inlet and the outlet temperatures
That guy did exactly what I'd fear a shop would do, screw up the installation and create an exhuast leak. Man, shops, if you are going to replace cats you better make sure it doesn't leak after you do your job! I hate the sound of exhaust leaks.
Very professional diagnostic and extremely helpful video. Thank you so much. I have similar symptoms on my Mitsubishi outlander 03. My downstream o2 sensor is reading about 0.7-0.8V after about one minute of accelerating to 2K RPM right after I release the gas pedal. Then after about 3-5 minute that downstream o2 sensor starts jumping and reading 0.3-0.5V like the upstream sensor. The temperature on the front and on the back of the catalytic are pretty much the same. Could you please advise me if my catalytic converter needs to be replaced? Thank you very much.
@@jimthecarguy I'm still wondering about the catalytic converter in my Mitsubishi outlander 03 and have one more question. If I'm randomly getting an obd code which says 'catalytic converter over threshold' is it possible that the problem is with the downstream o2 sensor? This sensor periodically reads up to 0.7-0.8V like I mentioned in my previous message but sometimes the reading from that sensor jumps all the way down to 0.1V. Would you advise me to change that sensor first before I replace the catalytic converter or in your opinion is it definitely the catalytic converter that's bad? Thank you in advance. And have a good one.
@@andriivladyka7126 hi, I would say the 02 sensor is ok. However the cat is probably bad. Have you tried cleaning both sensors and cats? Or have you already repaired your car?
Jim: Nicely done Sir. One Q: Isn't it possible that bad coils / misfire issue caused converter to plug up & a long highway trip AFTER coil replacement could have heated up Cats / removed plugging / restored proper exhaust flow? I've seen clogged Cats clear once engine management issues are fixed. I'm asking from the perspective of a DIY home mechanic who perhaps would want to try this economic approach first, before dropping $600-900 on that sweet new double Cat assembly ?
Yes it is possible. If there were misfire you could repair that first and then drive to see if it clears out. From my experience the cat is most likely going to have to be replaced. Thanks for your input.
Like the accent
How does experience say that you need a complete set of coils?! If it is COPs, and not one of the other potential causes, why do them all? Misfires are NEVER that easy to diagnose! A P030x code does NOT automatically equal COPs.
This seems pretty dishonest to me.
Dishonest my a-s . I have replace so many converters because of other shops just changing one coil and a month down the road another one fails. As you must know a misfire will destroyed a very very expensive converter assembly.. You have no idea what you are talking about.
Jimthecarguy - My point is that no level of experience is enough to look at a scan tool, read a P030x code, and know with certainty that you need to replace all the coils. There has to be some form of testing. Could it be COPs? Sure it could. It could also be plugs, valves issues, or several other potential reasons. A trouble code gives the symptom, not the cause.
The other issue is, if a coil is actually bad, then replace it. They do not need to be replaced as a set. The excuse of ruining the new cat a month later is not reasonable ......especially if you diagnose the misfire cause and fix it, not just throw potentially unnecessary parts at it.
@@mikenaples4046 Whatever you are entitled to you opinion.
How do we know the catalytic converter is “positively” no good ? What are the temperature differences supposed to be between front and back ? Also, did you replace the oxygen sensors when you replaced the catalytic converters ?
This guy has the best videos. Experience ,steady cam and good audio. No BS shtick ! Spot on.
Thank you for watching and your input.
Scotty Kilmer's videos.
Michael Brady , yep, Jim I straight to the point, and shows the best way to repair it. I have learned a lot from watching Jim's videos.
do you have experience with honda and acura vehicle do you know why honda and acura cars dont support o2 sensor 1 .... but it do support 02 sensor2 evertime when i use the scan tool
???
You have excellent teaching skills and knowledge jimthecarguy! I went to college 4 years and didn't have a phd instructor with half your teaching ability! This info is exactly what I needed after having a fuel injector stick open on my 05 F150 Triton 5.4. It hydro-locked on gasoline and bent a piston rod (107,000 miles). Check engine light flashed rapidly just as you said - I was 1 minute from home. Started engine an hour later ...white smoke billowed out tail pipe and strong gasoline odor. Fixed injector - all fine except loud knock started after starter came to halt. #4 piston rod bent. Will test cat after new engine arrives this week.
Attention Triton 3-valve owners - 05 models manufactured 1/1 - 12/31 have injectors prone to this failure. Replace yours today! Ford extended warranty on these engines to 10 years or 120,000 and warned dealers of catastrophic engine failure such as mine. Mine isn't covered due to time expiration, not mileage.
Thank you Jim. Great video! I have one question. Could the Oxygen Sensor just be bad & before changing the Catalytic Converter, just change the Oxygen Sensor, be a possiblity also?
That was a great visual using the heat gun. I just bought a used Vantage and can't wait to start learning how to use it.
To save the customer money you could’ve swapped out the coils from the other cylinders that were working. If the coils we’re bad then the problem would follow the new cylinder position, and thus , warrants a new coil. But to simply suggest new coils based on a code and then to further suggest replacing all oils that don’t even register a code is IMHO unethical.
Obviously you don't have any idea of the problems that this vehicle has with these coils but thank you for you opinion.
Blac Cayman He did demonstrate that method of testing the coils in another video.
but what would the inlet/outlet temps look like for a plugged cat. converter?
Thanks Jim, I am dealing with this same issue on 2007 f150. 5.4l. Your video will make all the difference.
👍👍
Great Video and Thx. Quick question. For a 2009 Mustang would u recommend using the OEM Ford Y pipe/converter for replacement or would an after market ypipe be ok? Had a rattle in one converter but its stopped. I've had 2 shops recommend the Ford OEM. Thx
It's shame that the infrared thermometer not functioning right when you need it . Great tips and video as usual !
I got a po136 06 Chevy trailblazer I know it suggests is a downstream O2 sensor but live data says the O2 sensor is working fine comes on after about a hundred miles got to realize this vehicle's got 205,000 me and I live in Chicago. Rust belt I do live data it shows CO2 sensors working fine. I really believe it could be the catalytic converter because if you press the gas there's hesitation that it normally wouldn't have. What's your thoughts
My O2 sensors in both banks are reading arounf 750 mV continuously (at idle and at 3000 RPM as well)
Also, the LTFT in both banks are almost zero, but at steady 3000 RPM, the LTFT go to -10 in both banks
What does this mean?
Cooler up front / hotter in back equals GOOD
hotter up front / cooler in back equals BAD
For no ads just go to.the end of video and start over👊 no ads TH-cam just kissed my ass 😂
Thanks for watching.
I have a 05 BMW x3
Both bank 1 and 2 sensor 2 are reading 92 and not moving. Could this mean that they are bad?
I do have p0420 and P0430 codes.
Could it just be the 02 sensors?
Great video Jim 👊🏻on a side note what the hell has happened to NAPA quality parts I’ve noticed a big difference last few years 🤷🏼
Thanks for an easily understandable video. I enjoy Scannerdanner's videos too, but you succinctly summarized the diagnosis of a bad cat for the shade tree mechanic.
Thank you for watching
I think I have a bad catalytic converter, Because bank 2 is mimicking bank 1, But I don't have a check engine light!? Why? Maybe later? Or can it just be 02 sensor bank 2?
First of all dont change anything til you get a code that tells you something is wrong.
If you have 2 banks like a V6 or V8 engine, you want to check the sensors on each bank.
Example, on bank 1, compare sensor 1 to sensor 2 with the motor hot and running and hold the rpms at about 2k rpms.
As long as the engine is hot enough, sensor 1 will jump up and down between 0.1 to 0.8 rapidly, and sensor 2 should be steady around,
0.5 to 0.8.
If sensor 2 is also rapidly jumping like sensor 1, then the cat might be bad cause is not heating up enough to burn gases.
To double check this, use a thermometer like the one in the vid to check the inlet and outlet temps of the cat.
Try to point the laser at the weld seams of the outlet and inlet. I find to get a better reading that way.
Hi i just have a question. Is the inlet temperature should be higher than outlet catalytic?
Or the post cat is should be higher? And what is the normal temperature for good cat?
Hi,Jim great video .Is it a good Idea to clean Catalytic Converter with oven cleaner?
No, use a bg fuel induction on the vehicle
Great video Jim. I didn't know any of that stuff. I have a Raytek, scan tool that works through my phone and a 1999 Ford E250 with 191k....need I say more...
Mine secondary O2 sensor moves reading moves around for like 2 seconds when I switch it to that reading, but levels out at like 0.075 shortly after and doesn't move that much. Does that mean it's still good?
I watch all your videos and learn a lot. May Allah grant you long life
Thanks for watching.
Try putting it on the pipe and not the heat shield the heat shield will read cooler you had it on the pipe at the front but on the heat shield at the back
I don't think this is a complete diagnosis you went straight for the coilovers and just replace them all I would have did a little more research to make sure that they were bad by switching them switches cylinders with the good one to the bad one and that I would have reset the computer to see if the misfire fault code came back I think this is the proper way to higher class the professional way to do it I think this is somewhat unprofessional to just assume that the part is bad without verifying it and to replace all 6 or 8 coilovers or all 4 whatever
Thanks for watching.
I watch all your videos and learn a lot. May Allah grant you long life
Thanks for watching.
I got this p0420 but the temp says cat is good, as I am getting hotter on the output . So what could it be?
I think you should only replace those coilovers if you could verify that they were bad that you switch him I wouldn't have replaced them all unless you think you have a race car or something cuz you never know some of them been replaced before Summit their coilovers
Thanks for watching.
Excellent tutorial on checking and verifying a catalytic converter problem. Thanks Jim!
thank you for helping other people / great detailed video
I'm a subscriber to your Channel so let me know what you think about my views
Good work jimmy did the old cat melt of did you get alot of rock's and chunk's out of the old cat.
This is the easiest video to follow. The other videos had me questioning if i really understand it or not. Lol
Thanks for watching!
Great video as always Jim. Have a beer on me or maybe 6 beers :)
Nice vid...helpful to see the diagnostics. My 2000 GMC Safari cat is fried!! That will kill a weekend fixing that beast. Thanks Jim!
which did you grab? the coffee or the beer? Good vid and info Jim! thanks!
So if o2 sensor didn't do what it was suppose to be doing how would you know that the o2 sensor didn't need replacement and not the converter itself
You will need to check the inlet and the output temperature to be sure the cat is bad.
Great video I'm getting po420 and po420 does that mean I have to replace front and back sensor
You will need to check the inlet and the output temperature to be sure the cat is bad.
i thought the BLINKING engine icon meant it WASN'T sure if there's a problem
Thanks for watching.
u will like the modus ultra with the graphing abilities
My car started hesitating after i took it to get tires rotated. found out the Mechanic took air filter out and didn’t put it back in when they did a point inspection. I put a new filter in but now i get the check engine light on. Changed the oxygen sensor out erased the code. 0420. Check engine light came out again. My question. What could a missing air filter cause the engine to cause the code ? Thank you
dirty MAF sensor ... mass airflow sensor
just beyond the air filter ...
with no air filter there was nothing to block whatever gets drawn into the intake ...
usually in the 'accordian' looking thing ...
(there's a special solvent/cleaner for MAFs)
would the voltage swing the same way for a lambda or A/F sensor on bank 1
Hi Jim. Great video. Please help me with my wife's 2013 infiniti jx35, V6 engine.
After getting the engine hot the cats were at around 850 degrees. The voltage readings were as follows: B1S2 - jumped between 0.070 and 0.080, B2S2 - jumped between 0.110 and 0.800, B1S1 - around 2.0v and B2S1 - around 2.2v.
Can you please help me diagnose this?
My pathfinder the same, u ever find out?
@@jasonfromm5637 he didn’t give enough info. And He didn’t say if the car even threw a code. 850 deg? V readings seem consistent
I have a 2015 GMC Sierra 1500 5.3l when I pull up the part for the converters it's showing a pipe with 3 parts on it and oxygen sensor for each how do I know which one is the bad one? I'm a widow and trying to figure out the cheapest way to fix this it's my only vehicle. Plus my truck has 167,000 miles is it normal for the converters to stop up that quickly? Please help!
I'm still wondering about the catalytic converter in my Mitsubishi outlander 03 and have one more question. If I'm randomly getting an obd code which says 'catalytic converter over threshold' is it possible that the problem is with the downstream o2 sensor? This sensor periodically reads up to 0.7-0.8V like I mentioned in my previous message but sometimes the reading from that sensor jumps all the way down to 0.1V. Would you advise me to change that sensor first before I replace the catalytic converter or in your opinion is it definitely the catalytic converter that's bad? Thank you in advance. And have a good one.
Can you borrow the laser thermometer from on of the big box store and check the converter as I did in the video?
@@jimthecarguyThank you for your reply. In about ten minutes after I started the vehicle I check temperature by the laser thermometer and the temperature is almost the same on the front and on the back of catalytic converter.
That's not really true that catalytic converter when we get really hot when you step on the gas when you're running it at 2 or 300 RPM to 3000 RPM that's the only time that catalytic converter will get hot and you should know that it doesn't get hot when you sit there and idle and you know that
WHATS UP WITH YOU?????????????? ARE YOU A TROLL? OR ARE YOU REALLY THAT DUM.
Jim, I drove a 91 Mazda pu for years with the check engine light on and sold it and that person drove for years with light on and never any other problem. In fact, I called the dealer and he said don't worry about it. In other words, is it always critical that the check engine light be addressed?
Yes fix the issue, just because you dont feel a difference doesnt mean you dont have a bad injector or cat and slowly destroying the engine slowly
I didn't hear you say anything about fuel injectors or fuel they have to be checked to the fuel injectors the fuel
Thanks for watching.
Hi, my check engine light on today . It say catalytic converter defect . But I have change it one month ago . Anyway I erase the code and check engine light gone . So my question is will it come back again. If so how long it will take to come back. Thanks
Golf 5 ( 2008 )
1.4 patrol engine
I drove with bad kat about a week but no engine light on and after I drove another week without Kat no engine light on . When I change my both Kat and drove 500km not engine light. Then I put fuel injector cleaner and drove another 150 km . And after engine light on and it says on my obd2 Kat defect
I absolutely get how to test the Cat by sensor and temp now. Thank you Sir 😊
Glad to help
How do we know if the back o2 isn’t bad ?
Can you check a catalytic converters with a OBD2 code reader on a vehicle that doesn’t run? Car won’t start with code P0430 but can’t check the CC bc it won’t run
nice video sir , tank you for sharing the information...🐒
Jim, could the up stream oxygen sensor be disconnected and removed, and if engine performance
has returned, would that now confirm I have a stopped up cat? I have checked and confirm all else
in system...everything ignition related, mass flow sensor, egr valve, throttle body, tps sensor, clean
air filter...everything under hood. Good fuel pressure confirmed. Presently engine will not run over
10 to 25 miles per hour. Removed egr valve and engine now performs somewhat normal. Reinstalled
Egr valve. I think if I remove upstream oxygen sensor engine will perform normal. Engine does use a little
oil. This may be my problem causing stopped up cat. Your opinion on removing oxygen sensor and
doing engine test drive. Your opinion on this test drive procedure. Engine is chocking up on acceleration.
Your thoughts please. Thanks..Jim.
I have a Mercedes Class C 2011 W204, the O2 sensor upstream is showing 2.0 (1.6 - 2.4) Volts and the O2 sensor is showing 0.41 (0.1 -0.6). The temp upstream is bigger than the temp downstream... Is there a probleme with the upstream sensor?
I have 96 Toyota Camry LE 4 cylinder with the P0420 code. I had previously did tune up in July changed coil packs and spark plugs and had to replace the distributer cap and rotor. The vehicle will start but will run maybe 2 -3 minutes tops then shut off and will start back up for awhile . Could I have more than just my catalytic converter as an issue?
Manufacturers should change the EML light from Yellow to Red...bcos all car manuals say warning lights in Yellow is nothing to worry about hence ..low screen wash warning is yellow...Bulb failure is yellow...low fuel is Yellow..how how we suppose to take EML light serious???..especially when the car is still running smooth...you think..oh..I haven't tighten my fuel cap😥
1997 F150 4.6 - do these numbers indicate anything to you? I don’t have a scanner . . . DRIVER side
Pre-CAT 494°
After-CAT 534°
(40° difference)
After-resonator 462°
PASSENGER side
Pre-CAT 436°
After-CAT 574°
(62° difference)
After-resonator 436°
Your digital heat gun is kinda junk lol
I had a p0420, used thermometer and showed the Cat is good (100° hotter downstream). The upstream voltages swings between 100mv to 900mv but the downstream shows 700mv - 800mv on idle, erratic on 50 mph. No leaks after exhaust manifold. Normal power. Fuel Trims okay. Could it be Rear O2 sensor?
Couldn't the O2 sensor be bad ?
Id love to know how much that job cost - all the coils and the 2 new cats. A big job and not cheap would be my guess
I’m $1400 lighter replaced the whole system yesterday new clamps new bolts 4 new sensors 🤦🏽♂️ 07 Jeep Grand Cherokee 170K oh and a week b4 discovered had a cracked radiator on the plastic neck nxt to the upper hose another $550 🤦🏽♂️ it’s like I’ve put a down payment on a new ride 🤦🏽♂️
Car sometimes after starting stays low RPM even if you floor gas pedal . I then turn off for about a minute then restart it and usually does the trick works normally . Usually works after doing it once . Lately , sometimes a few tries . About a week ago for the first time ever turn off died several times at home and very nearby ( a few blocks ) . Someone said it's probably a bad CC . Now I'm here trying to figure what to do . I'm hesistant taking to a shop because some mechs don't know what they're doing . Already paid for a throttle body with sensor replacement and that didn't fix it . And when they've tried to scan it it doesn't show any readings . And I've checked fuses
Awesome video. I learned alot from your video about this topic
Thanks very informative
Heh, if your check engine light is flashing pull over... I just replaced a cat on a Jeep. Lady said she drove it for a year with a flashing check engine light, and now needed it fixed for state emissions testing. Random misfire and a dead O2 sensor, burned a hole clear through the cat. Had to put on the dad voice and lecture her about ignoring the light
Jimmy when you checked the o2 sensor in bank one sensor 2 it was not fluctuating the proper way. It was the cat that was the problem. If it was a o2 sensor problem what would the scanner be showing? Did say it’s the sensor and not the cat.
Thanks. I have a toyota that had bad coils and plugs. The cat is not showing a code now but the monitors are incomplete. The scan tool says the cat is hotter upstream but it may be reading the difference between the wide band A/F sensor and the o2 sensor. Ill check with the IR thermometer.
On the left Cat that's not exactly efficient...what should the temp range be approximately? Thx
I'm trying to diagnose my catalytic converter, even though I don't have a check engine light on. The live data on my scan tool indicates that the voltage for my upstream 02 sensors fluctuate just as they are supposed to. However, my downstream O2 sensor (the one by the catalytic converter) remains flat at zero (0.0), so what does that mean in regards to the catalytic converter?
7:02 a beer will be fine thanks
So if catalytic work properly pre catalytic converters should be lower temp that post converter? Is this good assumption if both temp reading are same or pre cat hoter than post cat then consider replacing the catalytic? Please advice
The temp test is a start but its not the correct way, because the computer is set to go off by the smallest inefficiency. So the last car i worked on had a 100° drop from like 412 to 309 but was still setting the code p0429. So I changed the cat and light never came on again.
My down stream sensor is steady numbers and upstream sensors are moving kind slow I was told.
Car is bogging down.
Took sensors out drove around car drive fine, so, what’s bad , o2 or cat ?
I have a 2017 Hyundai Santa Fe and I noticed the inlet temperature was 200 degrees higher than the outlet and I have no check engine
Thank you Jim👍🔧🔩 your videos are always very informative.
Thank you for watching. Are you in the business Lone Star Auto?
If an cat converter is bad then air does does not move through the converter. When this happens which side would be hotter? It would be the inlet side because the heat just going to build up and not get through. Common sense. Not sure why a cat would be bad if the temps are the same on inlet and outlet
Great video Jim...
My new O2 B2S2 reading is in range
0.015-0.035V does it mean the cat is bad?
Where to buy solus pro snap on test tool
Nice video Jim. Have you ever used the method of how long the oxygen is stored in the cat? This test could be used to judge the life expectancy of a cat. Take care Jim...
thanks for you , it is very useful video
Was great video thanks
When rear oxygen sensor mimic the front one you say catalytic converter is not doing his job which is right
But by looking at pids how we know if it is completely blocked and collaps?
Explain the difference in temperatures when using the infrared temperature tool! I’m lost with what the differences in temps are supposed to be!
I don't understand why my check engine light is not lit up but I have a problem I think it's the cat converter cause I have no power esp when the engine gets hot
Does catcleaner work?
Where to buy scan tool
Po 420 means catalytic or can be o2 sensor my car was running with misfire I replace coils spark plugs pvc valve after that runs better but po 420 apear do you think cat is bad i removed cat and look normal no damages from one side because can’t see the oposite side any help is going to apreciate
From the research I was just doing, if the converter temp is lower after the cat then it’s clogged. So it appeared on your original system , the left converter was clogged and the right was emptied.
So are you saying that the temp further back the cat should be hotter than the temp coming in?
Yes
Yes, I seen that too?
Love the vid. I'm thinking my cat is starting to go myself. No codes whatsoever on the car. But I noticed some "popping/dinging" noises while driving today, and once I parked, I smelled a decent amount of sulfur. Going to give this a whirl on my troubleshoot journey before just assuming and making an expensive guess purchase.
I noticed you had the RPMs raised up in the second test I saw the differential in the background so does that mean you were wrong with the Inlet and the outlet temperatures
My oxygen sensor is not in the catalytic converter, but right behind it. Can I still use a scan tool to diagnose the catalytic converter?
That guy did exactly what I'd fear a shop would do, screw up the installation and create an exhuast leak. Man, shops, if you are going to replace cats you better make sure it doesn't leak after you do your job! I hate the sound of exhaust leaks.
Robert Wilson III there was no exhaust leak!
Oh, well then, that truck runs like shit! lol. It sounded like a leak to me, guess there's just a lot of mechanical noise.
Robert Wilson III Oh yes your right it did run like sh-t. Lol thank you for watching
My truck don’t have any codes but don’t have power, it don’t go more than 30mp
Very professional diagnostic and extremely helpful video. Thank you so much. I have similar symptoms on my Mitsubishi outlander 03. My downstream o2 sensor is reading about 0.7-0.8V after about one minute of accelerating to 2K RPM right after I release the gas pedal. Then after about 3-5 minute that downstream o2 sensor starts jumping and reading 0.3-0.5V like the upstream sensor. The temperature on the front and on the back of the catalytic are pretty much the same. Could you please advise me if my catalytic converter needs to be replaced? Thank you very much.
If the inlet and outlet are the same temperature and there is no exhaust leaks than it sounds like the converter is bad. Thanks for watching.
@@jimthecarguy Thank you very much for your reply and for your time. Have a good one.
@@jimthecarguy I'm still wondering about the catalytic converter in my Mitsubishi outlander 03 and have one more question. If I'm randomly getting an obd code which says 'catalytic converter over threshold' is it possible that the problem is with the downstream o2 sensor? This sensor periodically reads up to 0.7-0.8V like I mentioned in my previous message but sometimes the reading from that sensor jumps all the way down to 0.1V. Would you advise me to change that sensor first before I replace the catalytic converter or in your opinion is it definitely the catalytic converter that's bad? Thank you in advance. And have a good one.
@@andriivladyka7126 hi, I would say the 02 sensor is ok. However the cat is probably bad. Have you tried cleaning both sensors and cats? Or have you already repaired your car?
I have same problem, I wish I can use your help in your shop. Which city you are in?!
Jim:
Nicely done Sir.
One Q:
Isn't it possible that bad coils / misfire issue caused converter to plug up & a long highway trip AFTER coil replacement could have heated up Cats / removed plugging / restored proper exhaust flow?
I've seen clogged Cats clear once engine management issues are fixed.
I'm asking from the perspective of a DIY home mechanic who perhaps would want to try this economic approach first, before dropping $600-900 on that sweet new double Cat assembly ?
Yes it is possible. If there were misfire you could repair that first and then drive to see if it clears out. From my experience the cat is most likely going to have to be replaced. Thanks for your input.
Great Video.. Thanks man
Thank you for stopping by the shop