2020 Ram 2500 Exhaust Brake not working

[Bob Nichols]

I have a 2020 Ram 2500 Big Horn 4x4 that the exhaust brakes does not work at all unless in Tow/Haul mode and not very good then. A dealer has looked at it and replaced the Turbo and Exhaust modulator and this did not help. The system worked great until a few thousand miles ago then started doing this.

 

[crash68]

I'm going to throw out the guess that it's the torque converter not locking up or something in the transmission. Sorta going on the information that it works a little better when in Tow/Haul mode, that increases line pressures and lock up of the trans.
There's not much that can go wrong on the engine side other than the turbo vanes not stroking enough, but even still you would probably have issues on the boost side also if it was something engine or turbo related.

 

[Bob Nichols]

I had the truck to the Dodge dealer and as per them they could not find anything wrong with the torque converter so they said. I do question the knowledge of the mechanic. I have had another mechanic look at it and he couldn't find a problem either. The dealer replaced the turbo and actuator and did not help at all. He gave up. Hopefully I can get some ideas of what to look for and need to find another mechanic that is more qualified on diesel engines. My experience with diesels does not include baby engines like that. so kinda lost and Hate computers on them. Thanks for the info, if you can think of anything else please let me know.

 

[crash68]

if you can think of anything else please let me know.

Did a little Googling, it might be the exhaust pressure sensor causing the exhaust brake to be weak.
This is for the previous generation of Cummins but I would imagine the same controls and sensors apply although the location may differ slightly. Might be worth to clean and/or swap.

6.7l Cummins Exhaust Back Pressure Sensor & Tube Maintenance

Preventative maintenance on the 6.7l Cummins exhaust back pressure sensor and tube.

youtu.be

If the sensor doesn't pan out as a problem, I'd consider finding a dedicated transmission shop. Those guys usually know a whole lot more than a general shop mechanic about transmissions

 

[Bob Nichols]

I forgot to mention that the whole EGR system has been removed from the truck 20,000 miles before the exhaust brakes stopped working.

 

[Ritchie_Rich]

I forgot to mention that the whole EGR system has been removed from the truck 20,000 miles before the exhaust brakes stopped working.

Since it’s deleted and tuned, it could be the tune causing issues.

 

[Gr8bawana]

I forgot to mention that the whole EGR system has been removed from the truck 20,000 miles before the exhaust brakes stopped working.

 

[nlambert182]

The tune nor the delete impact the EB functionality. Did the dealer say if it had any codes?

I don't know what an exhaust modulator is, but if you mean exhaust actuator that could still be the culprit. They "can" fail and the turbo still build boost. I just replaced mine 2 weeks ago. Built boost fine, but zero EB.

If you can get someone to test the actuator to confirm that the replacement is functioning properly that would be my first stop. The only time my EB won't immediately kick on is if the trans is around 1100 rpms or lower. It kicks in any other time regardless of whether the torque converter is in lockup.

If you find out the replacement is bad... go to City Diesel and buy their actuator kit. No need to replace the turbo nor re-calibrate anything. It's bolt on and plug and play. Works really well.

 

[Ritchie_Rich]

The tune nor the delete impact the EB functionality.

Then what exactly does control the exhaust brake?

 

[nlambert182]

I think you misunderstand. The PCM controls the EB. Aftermarket tunes don't turn off the EB. The only setting that I've ever seen for EB on any tune was to change when it engages, allowing it to engage at lower speeds/rpms than factory. I've only seen or heard of that with the EZLynk. In the case of the OP and the EB not working, that's not the tune suddenly going rogue.

 

[ronheater70]

I second the Actuator. Many Times the sign of a failing Turbo Actuator is the EB also failing.

 

[nlambert182]

That was my first indication. I was coming down the mountain on the EB and it just disengaged. Shortly after I got a check engine light. For a time the truck was driving normally and building boost as normal but the EB would rarely ever engage. Codes told me what it was so I ordered one and drove it while waiting on the actuator to come in. Eventually I noticed that I was building boost, but not quite as much as before. Swapped the actuator and the problem went away completely.

 

[Bob Nichols]

The Turbo and actuator both have been replaced. Did not help any. Don't know how modulator was put on original post meant to say actuator. it just quit working. If I put it in tow haul the EB worked partially not like it used to.

 

[crash68]

@Bob Nichols came across the location of the exhaust manifold pressure sensor while looking some other info. The exhaust manifold sensor is in the manifold between cylinders 5 & 6.