2015 GMC exhaust brake

[JWM]

The exhaust brake on my 2015 GMC only works intermittently. Dealer said they didn't find any codes. Anyone else have this problem?

[DmaxMaverick]

Did the tech (??) actually diagnose the problem, or just plug in the scanner? The actuator could be physically damaged, and they'd never know it..... unless they actually look. This "condition" (diagnostics fail) seems to becoming more and more common.

[JWM]

They did a visual but said they didn't see anything. The tech told me the only time he saw a problem with the exhaust brake it gave a code that the vanes were stuck.

[cabletech]

The exhaust brake is only effective when the torque converter is locked. Drive the truck around in tow-haul and see if you notice it working. In tow-haul the torque converter will be locked in all gears except 1st.

Jay

[JWM]

It's the same in either mode. I have owned the truck since June and the exhaust brake has always worked. This just started on 020715. It's going back to the shop today. Because on the same day I also noticed a strong diesel smell when stopped. Tech said it had a bad gasket at the regen. injector. He said that may be the problem with the exhaust brake. I'm not sure how that would affect the brake but it needs fixed anyway.