Was having same problems, took to Michigan KW, they put new head on it for $13k and when I left , same problem. Limped it Albuquerque to Inland KW and told them how you fixed it and sure enough, problem solved!! I noticed it when I went to do a regen… dash said foot was on brake pedal 🤔
Thanks . I have learnt this myself by changing that valve out and poof still leaking and then found the exact issue . But ! I had no idea about the ecm droping the power . Thanks for that .
My 2016 is doing this. It is not leaking out of foot valve and brakes do not engage when the line is crimped. Could it still be the problem or should I move on? Thanks in advance
Thanks so much for the information. I've already run into this problem and it took me a while to figure out but I also had several other issues at the same time. Thanks!
I just fixed that problem but my truck keeps losing air and power, its not as bad as before but my mpg has dropped really bad. Even hauling light loads when I press the accelerator pedal sounds like a small whistle (it's not the turbo, turbo is working fine) sounds like air leaks from somewhere. You think it could be the intercooler?.
Yes you could have a boost leak but don't forget boost air also goes through the EGR system as well. I seen the corrugated connection pipe on the EGR valve crack and loose boost there. It connects to the exhaust manifold.
@Dakman Thank you very much for the reply. I'll check that. Also when I had the ABS valve problem, sometimes the Cruise control would not work, my mechanic told me that I should not have any more issues with it but yesterday the cruise control would not work again while I had a slightly loss of power, I'm wondering if something else is making the valve go bad or not work properly?.
Mine is doing that too. The whistle like air going through a pipe. Transmission warnings and abs warning shift restriction notification. Yet there are no active warnings or fault codes. With both parking brakes set. The sir pressure STAYS at about 112 psi. No increase or decrease in pressure, and no reaction to throttling or increased rpm
Like a sort of choked off whistling g spund like air going through a thing metal pipe. When decelerating in city driving the piping sound will happen with each down of up shift. During g the piping it feels like Jake's are applied, even when not, and as soon as piping chokes off, the power and forward thrift is returned. What on earth is going on? I have a feeling this is z simple problem. Maybe some kind of check valve or relay thereof. Abs warning lights flash as well. This 2023 t680 has only 83k miles on it
You are welcome. Thanks much for the super Thanks. Hopefully the video saved you money. I see alot of shops replace sensors and turbos not realizing it's actually a faulty ABS modulation valve that's causing the power loss because of the way the ECU is programmed
That valve Dr Paccar is talking about is a brake modulator valve, which is part of the abs, that valve has wiring going to it, which sends signals to the abs system controller, which includes sending a signal to the ECM, I know this because I am a diesel technician with over 30 years of experience. I am not saying that he is wrong, just stating that there is more involved than just the abs valve and ECM.
I'm 2016 Pete 579 is doing this now. It is not leaking from the foot valve and brakes do not engage when line is crimped. Could it still be the bendix valve or should I move on? Appreciate it
@@letstruckit9802Are the spring brakes chambers appear leaking and the service relay valve bleeding air . Is air traveling through the dash valves ? Check the anti- compound quick release valve , the backside internal rubber disc may have a hole in it .
Hi a comment please a question i have a 2019 peterbuilt 579 i can’t flatten my air bag , can’t move fifwheel. I replaced brand new. Mux solenoids bank 1 and brand new solenoids valves and got power coming. Still not working. Do you know why please. ? Thanks
Hey I'm having similar problem I got no throttle but my truck is equipped with a roll back every time you're on a hill that comes on but now is always on n I got no throttle
The T680 have the same ABS valve no matter which engine it has. However I'm not sure if the Cummins would have the same type of safety program in the ECM
Having this issue. But when I pinched the line nothing happens. What line do we pinch. Orange or green? If none of the lines activate the brakes it’s the foot valve?
Also why does mine come and go while driving down the road? I’ll have power than it’ll go away but it comes back but when issue arrives the brake lights are on
The Paccar MX13 is programed to reduce power once it sees the brake light switch is on and activated. This is a safety feature so you don't have a brake fire. Generally it's the front ABS valve that fails and bleads air backwards into the system. One indicator is air loss at the foot valve under the hood. The other way to test I cover in the video
So if I’m driving down the road and the power goes away and I see my brake lights are on while under throttle, is that a sign of the same issue? As well as air coming from foot valve
That's correct. Sounds like it's just starting but generally you can test it to verify by using the method covered in the video. You can change the valve yourself with general hand tools. It's right behind the front bumper . 4 bolts and the front bumper is off.
No it was not. If you have a ABS light on it's a different issue. If you have a KW T680 with ABS sensor issues but the sensor doesn't fix the problem then there is a broken wire on the left side under the cab near the driver's door. KW did a horrible job of routing ABS wires in that area and they rub thru
DR PACCAR, I have the mist strange symptoms, where there are no active warming or fault codes shoeing on 2023 T680 screen. Yet transmission warnings are going off with SHIFT RESTRICTIONS warning showing, TRANSMISSION FAULT WARNING SEEK SERVICE warning showing. A high pitched tutbolike sound thar gets cooked of with each gear while taking off from a trafiick light . But runs great on highways. Most of the time with both parking brakes set, and truck in neutral, and raising throttle and rom, there's no reaction on air pressure. If it's at 112, it'll stay there, not go up or down.
Oh heck NO. Nothing but problems, Our 2018 to 2020 cam issues, counter bores going bad and need cutting, BPV valve failures, DPF need replacing because they fail the flow test after the first cleaning. Just a boat load of headaches and problems. Even Peterbilt and Kenworth know they are problems. They only offered $18,000 for our 2019 Kenworth T680 and $20,000 for our 2020 T680 with the MX13. Those trucks only have 500,000 miles.
They all talk good more like actors than truckers, who knows what he is talking about in real life. This guy he calls him self Dr. paccar. Well, paccar, you got some pieces of junk engines which loves to be at shop than on road. It’s one junky piece off shit. Take from the real owner of that shit for last 8 years it bank rabs me. Don’t fall for the pretty truck if it’s packing paccar? back it up and run
I garrantee you that I'm not a actor. I spent 35 years of working on trucks with Cat, Cummins, Detroit ect. Yes I have been in and out of engines from in frames to out of frames. I have deep knowledge of ECM programming and parameters which helps me to understand issues. So with that being said the only reason I referred to myself as Dr Paccar because I figured out a fix to a problem that even the dealer couldn't figure out. I wanted to share this knowledge with everyone including owner operators so they wouldn't spend thousands of dollars on parts that wouldn't fix this problem. Although I called myself Dr Paccar I'm not a fan of the engine at all. I actually agree that it's junk and the design of the engine is horrible. Especially needing to remove a engine when a cam replacement is necessary. If I were to suggest a engine on the American market it would be the Cummins X15. Please don't make assumptions about me based on a video. I wouldn't take a Paccar powered truck for free.
I have a peterbilt 386 with the same issue I lose power wile driving If step on the gas it kind of feels like is a misfire I can't hear any air leaks the valve is different as well ill try changing that part and see if that helps thank you for making this video.
Who thought "right behind the front bumper" was a good place for critical braking components. Well done Paccar.
Having that same problem stuck at 55mph with air leak , I appreciate the video 🙏
Same here
Was having same problems, took to Michigan KW, they put new head on it for $13k and when I left , same problem. Limped it Albuquerque to Inland KW and told them how you fixed it and sure enough, problem solved!! I noticed it when I went to do a regen… dash said foot was on brake pedal 🤔
Thanks . I have learnt this myself by changing that valve out and poof still leaking and then found the exact issue . But ! I had no idea about the ecm droping the power . Thanks for that .
Nice job Dr Paccar 👍 They sure do keep making these trucks uglier year by year. Give me a W900L any day.
A Volvo look alike !
My 2016 is doing this. It is not leaking out of foot valve and brakes do not engage when the line is crimped. Could it still be the problem or should I move on? Thanks in advance
Dumb question. Im assuming this is done with the brakes released?
Theres also an abs module in the rear as well. I had mine go out on my 579 paccar. Kept dumping air it’s a time consuming removal process
Mine is doing that..... currently on its 2nd abs valve..
What was your solution?
Thank YOU SIR !!
Was about to replace the foot valve!
Nice video 👍🏽🙌🏼👏🏼👏🏼 what was the reason for U to replaced the sensor? My shut down the dpf fuel enable actuator
Thanks so much for the information. I've already run into this problem and it took me a while to figure out but I also had several other issues at the same time. Thanks!
thank you 👏 I have the same problem, and the mechanics are making me a new truck in parts!
I think i have this same problem. Cant wait to go find out!!
Great video, would you do a video on t680 adaptive cruise issues that keep popping up on the dashboard after being cleared thanks
I just fixed that problem but my truck keeps losing air and power, its not as bad as before but my mpg has dropped really bad. Even hauling light loads when I press the accelerator pedal sounds like a small whistle (it's not the turbo, turbo is working fine) sounds like air leaks from somewhere. You think it could be the intercooler?.
Yes you could have a boost leak but don't forget boost air also goes through the EGR system as well. I seen the corrugated connection pipe on the EGR valve crack and loose boost there. It connects to the exhaust manifold.
@Dakman Thank you very much for the reply. I'll check that.
Also when I had the ABS valve problem, sometimes the Cruise control would not work, my mechanic told me that I should not have any more issues with it but yesterday the cruise control would not work again while I had a slightly loss of power, I'm wondering if something else is making the valve go bad or not work properly?.
Mine is doing that too. The whistle like air going through a pipe. Transmission warnings and abs warning shift restriction notification. Yet there are no active warnings or fault codes. With both parking brakes set. The sir pressure STAYS at about 112 psi. No increase or decrease in pressure, and no reaction to throttling or increased rpm
What if the green line don’t apply the brake is it just the foot valve causing the same issue??? Please help
You’re the best brother Dr Paccatd Yeehaw thanks for your video, brother
I think you just fixed my issue. Thanks
Like a sort of choked off whistling g spund like air going through a thing metal pipe. When decelerating in city driving the piping sound will happen with each down of up shift. During g the piping it feels like Jake's are applied, even when not, and as soon as piping chokes off, the power and forward thrift is returned. What on earth is going on? I have a feeling this is z simple problem. Maybe some kind of check valve or relay thereof. Abs warning lights flash as well. This 2023 t680 has only 83k miles on it
Thanks
You are welcome. Thanks much for the super Thanks. Hopefully the video saved you money. I see alot of shops replace sensors and turbos not realizing it's actually a faulty ABS modulation valve that's causing the power loss because of the way the ECU is programmed
That valve Dr Paccar is talking about is a brake modulator valve, which is part of the abs, that valve has wiring going to it, which sends signals to the abs system controller, which includes sending a signal to the ECM, I know this because I am a diesel technician with over 30 years of experience. I am not saying that he is wrong, just stating that there is more involved than just the abs valve and ECM.
I'm 2016 Pete 579 is doing this now. It is not leaking from the foot valve and brakes do not engage when line is crimped. Could it still be the bendix valve or should I move on? Appreciate it
@@letstruckit9802Are the spring brakes chambers appear leaking and the service relay valve bleeding air . Is air traveling through the dash valves ? Check the anti- compound quick release valve , the backside internal rubber disc may have a hole in it .
I'm buying a 2020 or 2019 Paccar mx-13 peterbilt Looking at 3 range 300,000 -380,000 thousand miles what should I look out for and is it worth it?
Hi a comment please a question i have a 2019 peterbuilt 579 i can’t flatten my air bag , can’t move fifwheel. I replaced brand new. Mux solenoids bank 1 and brand new solenoids valves and got power coming. Still not working. Do you know why please. ? Thanks
Did you check to make sure air is going to those solenoids? We had air dryers get plugged and prevented air flowing to components
Can you do a video on DEF derate the code I keep getting is
P1514
P1518
P151A
Great explanation 👌 you're a paccar guy you pass the test
How can I check for this issue in a 2021 389 with an mx13?
I have a question, does that Valve create an steering stiff and a fuel power loss?
Omg!! Genius!! Better than mechanics!
Hey I'm having similar problem I got no throttle but my truck is equipped with a roll back every time you're on a hill that comes on but now is always on n I got no throttle
Do you happen to know if the T680 with a Cummins engine has the same brake modulator valve setup?
The T680 have the same ABS valve no matter which engine it has. However I'm not sure if the Cummins would have the same type of safety program in the ECM
Having this issue. But when I pinched the line nothing happens. What line do we pinch. Orange or green? If none of the lines activate the brakes it’s the foot valve?
The green hose and then watch the slack adjusters on the steer axle only to see if they move and apply. Make sure to use needle nose vise grips
@@Dakman I just disconnected it and plugged it and it activated the front brakes. Thanks for your informative cideo
Hi, mine has 2 split green lines, do I pinch both?
Having same problems thank u sir well done perfect explanation. 👌
Also why does mine come and go while driving down the road? I’ll have power than it’ll go away but it comes back but when issue arrives the brake lights are on
The Paccar MX13 is programed to reduce power once it sees the brake light switch is on and activated. This is a safety feature so you don't have a brake fire. Generally it's the front ABS valve that fails and bleads air backwards into the system. One indicator is air loss at the foot valve under the hood. The other way to test I cover in the video
So if I’m driving down the road and the power goes away and I see my brake lights are on while under throttle, is that a sign of the same issue? As well as air coming from foot valve
That's correct. Sounds like it's just starting but generally you can test it to verify by using the method covered in the video. You can change the valve yourself with general hand tools. It's right behind the front bumper . 4 bolts and the front bumper is off.
I don’t have a air leak but mine is surging with the cruise on gets worse the faster you set it
Is that truck disc brakes in the front?
Did you or the driver get a low fuel pressure code?
Amazing..did that apply the brake to both steers?
I did have that same issue I end paying the dealer 2700 dollars for a part that only cost 365 dollars and You can install yourself
Im having this issue. Does the whole thing need to be changed or just one of the modules?
Just the ABS valve behind the front bumper
Question dr, Paccar was the ABS warning signs light on ??
No it was not. If you have a ABS light on it's a different issue. If you have a KW T680 with ABS sensor issues but the sensor doesn't fix the problem then there is a broken wire on the left side under the cab near the driver's door. KW did a horrible job of routing ABS wires in that area and they rub thru
I have similar problems but I also have a low fuel pressure code and high lambda. Ever came across this problem. Thanks
Nice video man Thanks
DR PACCAR, I have the mist strange symptoms, where there are no active warming or fault codes shoeing on 2023 T680 screen. Yet transmission warnings are going off with SHIFT RESTRICTIONS warning showing, TRANSMISSION FAULT WARNING SEEK SERVICE warning showing. A high pitched tutbolike sound thar gets cooked of with each gear while taking off from a trafiick light . But runs great on highways. Most of the time with both parking brakes set, and truck in neutral, and raising throttle and rom, there's no reaction on air pressure. If it's at 112, it'll stay there, not go up or down.
How to bypass to get home
Is a paccar mx13 a good engine?
Oh heck NO. Nothing but problems, Our 2018 to 2020 cam issues, counter bores going bad and need cutting, BPV valve failures, DPF need replacing because they fail the flow test after the first cleaning. Just a boat load of headaches and problems. Even Peterbilt and Kenworth know they are problems. They only offered $18,000 for our 2019 Kenworth T680 and $20,000 for our 2020 T680 with the MX13. Those trucks only have 500,000 miles.
So.. in theory, if the orange line is pinched off, the rear brakes apply (in a rear ABS system on the Fritz senario)???
I have not tried that theory because I have not run into that issue as of today
Great tip thank you man
2019 peterbuilt doing the same thing ,25 percent throttle after hitting the brakes
Mite be the best video THANK you 😮😮
Great job...thank you..
Air pressure to 135, what lol. I hope the compressor shuts off before that or you have even bigger problems lol. Good video though buddy
Great video
Thanks!
‼Perfect
👍😉😀
👍
Wey better than other ppl getting paid and not good 😊
They all talk good more like actors than truckers, who knows what he is talking about in real life. This guy he calls him self Dr. paccar.
Well, paccar, you got some pieces of junk engines which loves to be at shop than on road. It’s one junky piece off shit. Take from the real owner of that shit for last 8 years it bank rabs me. Don’t fall for the pretty truck if it’s packing paccar? back it up and run
I garrantee you that I'm not a actor. I spent 35 years of working on trucks with Cat, Cummins, Detroit ect. Yes I have been in and out of engines from in frames to out of frames. I have deep knowledge of ECM programming and parameters which helps me to understand issues. So with that being said the only reason I referred to myself as Dr Paccar because I figured out a fix to a problem that even the dealer couldn't figure out. I wanted to share this knowledge with everyone including owner operators so they wouldn't spend thousands of dollars on parts that wouldn't fix this problem. Although I called myself Dr Paccar I'm not a fan of the engine at all. I actually agree that it's junk and the design of the engine is horrible. Especially needing to remove a engine when a cam replacement is necessary. If I were to suggest a engine on the American market it would be the Cummins X15. Please don't make assumptions about me based on a video. I wouldn't take a Paccar powered truck for free.
Wow
I have a peterbilt 386 with the same issue I lose power wile driving If step on the gas it kind of feels like is a misfire I can't hear any air leaks the valve is different as well ill try changing that part and see if that helps thank you for making this video.
Did you get your power back or did it make a difference please let me know.
Thanks