Hi, guys,

Lurking forums for awhile as I learn. Have a question and hoping some of you fine, knowledgable folk, might have an answer.

Working on a customers truck that has been deleted and tuned with a switch from another shop, and have replaced a stock turbo (not much choice under parts warranty), and are experiencing an issue with the Exhaust Brake not deactivating under higher speeds. It will deactivate and release finally, decellerating to about 20 mph from a few data logs with a Snap-on tool. Trying to find what inputs are used to deactivate and release the exhaust brake (Accel pedal position should release it, but it does not) and at what values are used as it determines this strategy to release the exhaust brake.

From the limited service information I have available, and operation manual, this should use the accel pedal position, and when it sees fuel delivery drop to 0%, to release. However, the fuel delivery seems to stay above the 5k psi range. Hope I'm tying this together well enough into words.

Low speed Exhaust brake operation seems fine, and automatically engages and releases the exhaust brake cruising around with in town speed limits.

Highway is different.

Trying to find what's keeping it on. Any help is awesome.

Thank you!