Cummins ISL 400 ENGINE COMM ERROR

I have seen many people asking about this "ENG COMM ERR" and the sweeping gauges. It happens so randomly its tough to get a good diagnosis, but, thankfully, as the service tech was in the rig, with his computer hooked up to the 9 pin connection and it happened, as soon as it started, the computer lost communication with the ECM, he tried the rear 9 pin and the same thing, no communication, so that told him that there was a power or ground issue to the ECM and was likely NOT the ECM itself. Thankfully.
The "ENG COMM ERR" happens when the ECM can't be found and the gauges sweep because they are searching for a value to be set at. All this seems to happen because of a bad component on the main power board, ours seemed to be caused by a faulty ignition relay on that board. Frank is a GREAT man and resource, I can't thank him enough for his help and patience.

FRANK MCELROY
M-TECH ELECTRONICS
(908) 399-3063

We have had an electrical gremlin running around the engine for about a year, randomly, the rig would lose power, and the dash would display "ENG COMM ERR" and the gauges would sweep back and forth. I *hope that this was it...

These boards are repairable, Frank McElroy did an awesome job, he had our board repaired, tested and back to FedEx for an overnight flight back to us with in 2 or 3 hours of receiving it! So far, so good!

**MAKE SURE THE POWER IS OFF TO THE BOX BEFORE REMOVING/ REPLACING THE BOARD!!! ** This is a 2006, Cummins, ISL 400, 8.9L

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