Epg1/epg2/veb break bridge active code truck rough idle

Diagnostic Assistance Request - Volvo VNL with VED12C Engine

Dear Forum Members,

I am encountering a persistent issue with my 2002 Volvo VNL, equipped with a VED12C 465hp engine. The engine underwent an in-frame overhaul 219,000 miles ago, with all new components installed. For the past three years, the truck has operated without any significant problems.

Recently, I have been experiencing a series of fault codes, specifically:

* MID 128, PPID 122, FMI 5 - VCB Break Status Electrical Fault Active
* MID 128, PPID 123, FMI 5 - EPG2 Start/Warmhold Electrical Fault Active
* MID 128, PPID 124, FMI 5 - EPG1 Engine Break Electrical Fault Active

The issues began when I engaged the exhaust brake (stage 1) and subsequently hit a pothole. This was followed by a noticeable fuel knock that occurred only when the jake brake was active. The knock persisted for several miles, although there was no loss of power or rough idling at this stage. After dropping off the trailer, I observed a surging problem, and the jake brakes appeared to be stuck in the open position.

Initially, the diagnostic laptop indicated an issue with injector 5. Despite replacing the injector and subsequently the injector harness (due to 발견된 damaged wires), the rough idle and slight smoke persisted, although the injector code was resolved. The engine seems to be "fighting" the jake brakes, potentially indicating a stuck plunger in the exhaust rocker arm. Upon inspection, a slight condensation was noted on the valve cover, but all valves appear to be in good condition.

As part of the troubleshooting process, I have replaced the ECM, VECU, jake valve body, and the EPG solenoid located on the passenger side of the block. I have also recorded a video demonstrating the rough idling and captured images of the fault codes.

I am seeking assistance from the community to help diagnose and resolve this issue. Any insights or suggestions would be greatly appreciated.

Thank you for your time and expertise.

 

Yes sir I replaced the whole harness this harness had all the sensors boost cam crank coolant temp and level sensor etc