How to test Intake Valve Control Solenoids (codes P0028, P0082) - Subaru
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- เผยแพร่เมื่อ 16 ก.ค. 2024
- On this system the intake valve lift is varied by two different cam lobes. A low lift lobe and a high lift lobe. I misspoke in the video calling this a variable valve timing or VTEC mechanism. This system does not vary cam timing, but it does vary intake valve lift.
What was unusual with this fault was when you have "circuit low" type codes, this is almost always an electrical problem to the solenoid or the solenoid itself is open. However everything tested fine electrically and we found that this engine was very low on oil. Once we added oil, these codes did not return.
Engine Performance Diagnostics chapters 2 and 3
Symptoms
- check engine light (P0028, P0082 codes)
- poor performance
Fix
- added 2-3 quarts of oil to the crankcase
Tests shown
- how to identify oil switching solenoid valve circuit design
- how to identify variable valve lift pressure switch circuit design
- how to test both the solenoid and pressure switch
- why manufacturer flow charts suck
Tools used
- incandescent test light
- scan tool
- lab scope
- digital multimeter
Playlist
- (Chapter 3) Transistors, Solenoids, Computer Controlled Output Testing • (Chapter 3) Transistor...
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For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
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On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!
Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC. - ยานยนต์และพาหนะ
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Your consistentcy of putting out these videos, all these years has been amazing. You're always enthusiastic, articulate and go that extra step which is obviously time consuming to make sure students get everything from the smallest detail to the big picture. Just wanted to share my appreciation. Your premium channel is worth the fee many times over, I enjoy it very much. Thanks for caring and sharing the passion Paul.
I don't think I'm going to test through the ECU because I'm not willing to risk frying it, but I'm learning a ton from this video. Thank you for posting it!
Nice one Paul.
What you showed in this example is, one should not overthink it, always start with the basics.
I saw this exact same thing on another Subaru with the same issue. The oil was low and dirty. It caused the SAME codes. Car owners that do NOT check their oil are asking for more issues than they can imagine. I hammer this into my kids heads and my wifes head. Changine oil and maintaining it is the CHEAPEST insurance for a great running car. This told me TWICE now that this vehicle is reliant on proper oil level for proper operation on that oil pressure switch. Wow! Great method for checking it too. Your test works and as you said saves time. Great job!
I have been troubleshooting electronic engine controls for 18 years, and I feel the same way on flow charts. You take a simple, and effective approach to trouble shooting and relay the system in a very understandable way. Keep up the great work. The younger guys starting out in this technical field, will certainly benefit from your knowledge and use of the scope as a major tool in troubleshooting. Great videos.
Great wrap up at the end with the flow chart, I totally agree that it's about time we start getting the respect we deserve for the knowledge we have. I just got your e-book last week and as the youngest guy in a workshop of old school mechanics I'm really enjoying going through it since I had no one to teach me these methods previously.
Really appreciate your videos and work, keep it up!
You are a freak! I have degrees in mechanical, electrical, and industrial engineering and you amaze me. Your logical reasoning is what is needed in the fundamentals of engineering. I consider myself very good at logical reasoning and very much appreciate your skill level. You need to simply forward a video to the headquarters of Subaru and wait for a call. I have a lot to learn from you in vehicle electrical systems. Thank you for taking the time and effort to teach us!
Wow what a compliment coming from someone with your background and knowledge. Thanks so much! I'm just a guy who barely passed high school who found his calling in electronic classes at the tech school i went to. Then I went into the field for 8 years before coming back to teach at the same school (Rosedale Technical College) and have been teaching on this subject for over 19 years now while still troubleshooting cars both in the live shop at our school and for different garages. So I've just had a lot of practice on teaching certain subjects. More from a mechanics mindset though. I know some of my theories are off but if I can say to someone 100% of the time if you have this problem then it will be this solution. Who cares if my theory is off a bit 😉
I got a P0028 last week and ran into this flow chart I was shocked. The thing that saved me is the passenger bank uses the same system I tested the known good then made my comparison. Great work as always
About the flow chart, Thank you Thank you Thank you. Sometimes i think the engineers have stock in the parts industry. And your right some of us and i do say some of us , well maybe most of us have a least a 3rd grade education and can read. WHY NOT tell us how the circuit works and leave the flow chart to us. Very good my man, very good indeed.
Bought an '07 Outback for my son and it threw a P0028. Having an electronics background I found your video really good. I am getting a burning smell and found the oil pressure switch that seems to be leaking by. I hope this is the problem but with your video, I really have a good sense of where to go. Thanks!
thank you!
Tiene usted toda la razón señor Paul, existen métodos mas rápidos y prácticos para diagnosticar que con conocimiento y cuidado pueden llegar a ser mucho mas efectivos que un diagrama de flujo elaborado por los ingenieros. Gracias maestro.
Great video man! Wish there were more guys out there like you!
That is awesome man! I think it will do you good to have your background and I couldn't agree with you more about being proud of it!
Mr.Danner.Your more of an Engineer than they are...Great video
Great video once again Paul!
I could not agree more on how poor the OEM flowcharts are.
The very first thing they should have said to check when that code is set is OIL LEVEL.
Thanks.
Great educational video, as always. It was the rant on flowcharts at the end that earned a big LIKE though! This code's flowchart was a great example of how bad they can be. Truly awful! Flowcharts can be worth skimming through for some quick spec's and function, but often waste a lot of time. Thank you for trying to reach out and get these fixed for all of us!
thanks man
If you follow that flow chart you'd end up putting in a new oil switching solenoid valve giving it back to the customer and then they'd seize their motor because it had no oil.
Great video I've learned many things in the short time since I found your channel.
Great diagnosis as usual Paul 👍🏻
I didn't notice any other lights indicating low oil level. This thing was 2.5 quarts low!!
Another good one, Paul. Thanks!
Great diagnosis as always!!! I couldn't agree more on the flowchart... it's horrible... i had the same problem today (p0028), and the oil pressure switch turned out to be the culprit... they don't even mention it...
Thanks again, correction made. I am grateful that you caught that early for me. I owe you one.
You wanna read something strange. I haven't used a trouble chart in ages. All I want is the circuit description in detail and a nice wiring schematic. I wholeheartedly agree with you on that one Paul.
Great teachings you are giving out bro scannerdanner. Thanks so much
Good question. The digital voltage reading is an average of the on/off duty cycle. It increased in voltage because the on-time increased. If this was ground side switched the voltage average would drop as on-time increases.
The last minute of this video describes perfectly what every other Auto Technician thinks of engineers. I doubt if even half of these people even know how to check the oil level in their cars.
I’m in awe. Dan is a certified car guru
Paul Danner 😉, thanks V!
good video,2 things one is bypass to monitor a reaction and two polarity to determine jumpwire placement. polarity a little confusing because testlight will show different readings based on harness connected or harness disconnected.
I am using this video to trick an 07 ECU into thinking my non-VVL engine is running VVL. These are exactly the voltage readings i needed to see to wire the relay.
Why would they give you the information you need, when every misdiagnosis means an extra part sold for them?
Thanks for the video and the explanation of the electrical system. Hopefully I can get more insight into my recurring P0028 fault by performing these tests.
thats awesome Edmar! thank you
Good vid, defiantly a good case for p.s.s and pull downs
-Brandon
I love your T pin tool..thanks for the video..i learned a lot.
"Why are they doing it this way? I can't answer that.... Obviously it's for circuit monitoring that they're doing it this way." ROFL. I'm joking though man, seriously good video and people like you are very kind for taking the time to capture and share this stuff!
Observation of the ECM schematic would explain it
Flow chart should start with
#1* Check engine oil level and quality😁
yep.. that will set a vtec code
I just watched motoyam82 on the Subaru , love all these vids from scannerdanner south main and motoyam82
Amen brother!!!!! We need proper info for proper diagnosis!!
Thanks Jeremy!
Thank you for all the information this is the best video on you tube . Im definitely subscribing to your chanel.
You are correct, but if done properly it is THE tool to use. Remember my test light was connected to B (+) and it was finding a ground through the solenoid winding when plugged in. Unplugged the yel/grn wire did not light. Plugged in it did because it was finding a ground through the solenoid winding and the other wire that was a constant ground.
The duty cycle at idle may be to monitor the solenoids / make sure they are connected, it may be a current monitoring signal.
Awesome troubleshooting techniques my man, absolutely very informative, in terms of the diagrams and etc you need to understand this is a very much money driven industry and those vendors purposely make it that way so they can secure their own jobs, sorry but it is just the way it is. Nowadays many industries are operating that way unfortunately.
Yes, which is exactly what my ebook is all about teaching.
ScannerDanner hi . In the video you keep saying will cook the ECM if you touch the ground wire and you were using test light .and you already touched ground wire when you try to identify positive or negative switch . Why test light 12v supply goes through solenoid then ground back ecu will be fine . What is Rule s for avoiding damaging ecu . Thank you paul
Thank you very much
hey... that is some nice troble shoting. following your videos all the way from denmark i europe :)
Awesome, you sound like me! I couldn't agree with you more, thanks
your comments in the last minute of video are spectacularly correct. lets have some sense instead of bulls#it. I get sick of reading a flow chart that ends with substitute known good ecm. I don't have a cupboard full of them to swap and code. good video again
Paul, Nissan uses a similar system 'cept is a different code P0011 ivt control. It is a pulse width ecm controlled two wire solenoid, at idle you have 14 volts on both wires and off idle you have control on one wire. Had a car the other day with low oil setting that code, look for it. Excellent video btw.
Paul that was fantastic. I suspect the OEM'S are not sharing the correct diagnostic repair procedures to 3rd parties. I would suggest that the dealer network repair flow chart differs from what you have. Auto manufactures are required to produce specifications on their vehicles and you see what they are sending. The right to repair bill is being challenged by OEM'S. That flow chart was an insult. Glad to hear your thoughts on a subject that seems to be getting worse. Well done !!
I Respect you.scannerdanner !
Awesome job!! Thanks
main you couldn't have done it better thts Absolutely correct
Other way to find power or ground side switch, there will be between 0v to 12 volt on control wire (two resistances are in series, one in the pcm and other is solenoid itself) when ign switch is turned on. other wire will be if 0v then this is power side switch or 12v (ground side).
Amen Brother...give us INFORMATION to properly repair these vehicles.
hi, at 11.14 in ur video you said that test light is lighting because the resistance of the solenoid is high, but i think it is lighting because resistance of the test light is high and because of that you were not able to pass enough current. if the resistnace of test light is low, then u pass more current to solenoid and it works. higher the resistance lower the current and viceversa. It worked fine with your jumper wire because it has less resistance.
I just looked it up, it is exactly the same format as the one I showed.
Did you go under "system diagrams" then "engine performance"?
couldn't argue with that, but then I wouldn't have this great video :-)
Excellent video and excellent
Hope you the best .
My favorite part starts at 20:50...Epic.
motoYam82
Hey Paul I'm an electrical engineer and completely agree with you about engineering flow charts. These flow charts do not "promote" the understanding of basic electrical principals of ECM sensor operation and processing as well as ECM control methods of solenoids. So was it the fact that the "oil pressure" switch was not being activated by proper oil pressure (due to a lack of oil) or was it the Cam sensors did not detect a change in engine timing that generated the error code.
Great work Paul, keep it up , you are a great teacher, wish some of my Professors taught the way you do !!🙂
Great question! To be honest I'm not sure, it's been along time. I suppose the arguement could be made for either. Thanks so much for the encouragement!
Very helpful, thankyou
You're welcome!
The reason the ground side of the solenoid returns to the computer is to prevent ground bounce and ground noise from affecting the position of the solenoid.
Never used the powerprobe 3 so I don't think I could comment on that. I just like my old fashion test light.
Thanks bro
I'm getting closer and closer to buy your premium!
Rule #1 :Never leave an engineer unsupervised. Rule 2: See rule 1
You doing very good job 👍👍👍👍 nice video 👌👌👌👌👌👌
You teaching very good you good teacher 👌 👌👌👌👌
This engineer problem has been around since 1980 when the first computer was installed in a car
good video, and fancy computer tool you have there. the skills you used were some basic multimeter skills that everyone should know, but very many do not. Measuring Resistance (in ohms) would show if you had a short or break in your wiring to harness. I can see why their flowchart mentioned to do this. You were measuring Voltage of the two circuits which could have shown correct voltage but if you had a break or short, it might not have been grounding out unless the vehicle was shaking underload
AWESOME VIDEO NORTHEAST AUTOMOTIVE INC ROCHESTER NY
G johan- because when the plug is connected the component in this case the switch is consumping the voltage and keeping the switch closed.
It certainly can be dangerous but only if you are using the wrong polarity and the driver happens to be "on". If the correct polarity is used, even with the driver "on", there is no danger as there would be equal potential across the emitter, collector circuit. Equal potential = no current flow through the driver.
Mr danner where can i get a copy of your book
That's was the best way to end that video great video..flow charts are a joke
I'm not sure, but certainly that is a valid argument. The 20% duty command could also be simply for diagnostic purposes?
You know, I didn't even check. I guess I just wanted to show the manual method. I should have though. Sorry about that.
Was it knocking with its 4th cylinder's piston when you were revving it up on the 20th minute of the video? There was a strange knocking on throttle closing ))
Cool video, I was wondering if the solenoids were negative switched and what state the oil pressure switches were when active / not active.
Great video brother. Would this be similar to the setup on a Colorado 3.5 L5 cam actuator ? God bless
thank you from iraq
Un saludo desde Perú 👍🏽👍🏽👍🏽 nice
Paul when you revved the engine and got the oil switch to open, the voltage on channel 1 also increased activating the solenoid. Was this an average voltage or actual voltage????????????
Thank you very help full. But still do not understand after leaving the car park for six month where oil disappear. No leaks nothing
The dealer who I bought my car off of I brought my 2006 subaru forester to them. Got that code I had no oil. They filled it up. but now something on the bottom of the motor is burning after driving for like 10 minutes. The code hasn't came back but I am curious why it's doing this now. The car has 97700 and I just did an oil change two weeks ago. Any idea
well said!!! at the end
I did misspeak there didn't I. The test light was bright because it was a low ohm coil, not a high ohm coil. I'm going to put a note in the video. Thank you and sorry for the misinformation.
good video
Where do you get your wiring diagrams from what service do you use?
@scannerdanner I think I may have fuel delivery problem.. Stft are good at idle plus went over entire intake whit propane, no rpm increase however system stays in open loop until I goose the throttle.. Car stills has miss at idle no load.. I'll try changing fuel fillter first.. this system has no test port.. But 02 show very very lean less then .10 bank 2.. Another thing I noticed was Pcv system on valve covers are rigged.. Lol whit a hose and spark plug boot.. Isn't the system suppose to regu
Thank you,
I have a Subaru Forester and the engine is probably a Legacy DOHC, there is 12 volts on the solenoid socket after switching on the ignition, is that correct? Thank you for the answer, Jozef.
My 2008 Subaru OB with the 3.0 six codes out with P0026 and P0028. I checked the oil and it's perfect. The acceleration at times is stumbling when pressed, but when gentle is smooth as silk??? I have a code reader and the code clears (of course), but comes on after 1/2 mile or so. Once when I turned the engine off, with the CEL light on, when I restarted it 2 hours later, the CEL was out, but came on after several miles. Whasssuppp?
we had one of these with the same code that was leaking oil up directly through the switch itself
I know, right?
Mitchell On Demand
like you wrote
step 1 should be : check the oil level
it make sense on a oil pressure working system.....
moreover i guess there is certainly a pressure valve upstream to avoid spreading oil in all the system under a specific pressure no ?
not low oil pressure idiot light or sender connected to the ecu ?
The tests he did proved circuit integrity, an ohm test on the wires wouldn't have shown better results than his tests because he's not only doing voltage measurements but also voltage drop tests.
Engineers write in ohms tests because it's what they are accustomed to, for them the system isn't mounted in a car and interacting with other components. For them it's on a test bench with a note saying it doesn't work.
Freind found an ear plug in a brand new cars vvti. Out of the factory.
If I were to disconnect the connector to the solenoid and use a power probe to power it up that would be the same test right?awesome videos by the way!
8:20 I thought there were times that it wasn't recommended to use a test light on a circuit that is tied into the computer, or am I mistaken? Also, I wasn't sure why, with the solenoid unplugged, you were seeing the positive on the yellow/green wire...but when it was plugged in, you didn't.