Exhaust brake issues

[Ozymandias]

Some one else said in an other forum that the exhaust back pressure sensor can be clogged and misreading. Causing all kinds of mischief in the ECM.

 

[EZeis]

Some one else said in an other forum that the exhaust back pressure sensor can be clogged and misreading. Causing all kinds of mischief in the ECM.

Yes, I know that parameter is part of it. It's on my list to clean. Mine doesn't go to zero with the engine off. I'm not sure if that's normal or a problem. The sensor could be bad if it's supposed to go to zero.

Can some of you please verify if your exhaust pressure sensor goes to zero with key on engine off?

 

[Topzide]

@EZeis, Here's a screen shot from my FSM. Might help with what to check.

 

[AH64ID]

Yes, I know that parameter is part of it. It's on my list to clean. Mine doesn't go to zero with the engine off. I'm not sure if that's normal or a problem. The sensor could be bad if it's supposed to go to zero.

Can some of you please verify if your exhaust pressure sensor goes to zero with key on engine off?

What does it go to?

 

[EZeis]

What does it go to?

7.1 kpa

 

[AH64ID]

7.1 kpa

That’s 1 psi, probably close enough to zero but still worth a clean.

 

[EZeis]

@EZeis, Here's a screen shot from my FSM. Might help with what to check.

View attachment 143298

Thanks! I appreciate it! I wonder which ambient temperature sensor they are using? I'm showing 3 PID. I will check those to see if they are reporting as expected. Coolant temp is reporting accurately. Exhaust pressure is reporting but as I stated before, it doesn't go to zero. Lowest it goes to us 7.1 kpa, which could be a problem.

Is that an actual FSM or pulled off Tech Authority?

 

[AH64ID]

Ambient air temp comes from the sensor in the intake just after the filter.

 

[lpennock]

7.1Kpa is 1.02lb/sq in. Probably not an issue.

 

[Ozymandias]

That’s 1 psi, probably close enough to zero but still worth a clean.

Make sure that it doesn't measure atmospheric pressure.
Some sensors really measure Zero which doesn't exist in that situation.

 

[AH64ID]

Make sure that it doesn't measure atmospheric pressure.
Some sensors really measure Zero which doesn't exist in that situation.

Yes, which is why I was wondering what it was reading. If it reads absolute it would be really low at 1 psi, so that shouldn’t inhibit operation.

 

[Topzide]

@EZeis, From my factory manual. Figured it was worth looking as the EB works through the turbo on our engines. Not much difference for the 2014 to the 2018 on the engines. Let me know if there's anything else that might help.