2009 Cummins ISX CM871 communication error? or not?

[codlv]

(09-25-2023 )Rawze Wrote:  

(09-25-2023 )codlv Wrote:  

(09-25-2023 )Rawze Wrote:  What you describe is typically one of 2 things.

A known wiring issue that Pete and KW trucks suffer.
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OR.. a bad/flaky ecm.

I purchasesd an OEM Cummins Reman ECM and had it programmed at the stealership, that is all they did, work is being done at a different location. Had a small fleet up til last year and had an 09 Volvo with the same engine, it started acting the same way and after chasing the problem before finally determining it was the ECM I decided to go ahead and start with the ECM this time, but that hasn't solved the problem just yet, even with the 2 new engine harnesses. We'll check those spots for sure.

To check the ecm ...

New or not ... Testing the ecm for this known issue is as easy as banging on the ecm (almost hard enough to dent its casing bit not quite) while engine is idling. If it cuts out then its a bad ecm. Simple as that.

It passed the bang test but KW is going to bench test it in the morning regardless. We jiggled wires, checked fuses, just about everything you can think of. My harness doesn't go around the back of the engine like the pics I saw, but it does go around the front, and it's brand new now. And my fuses are on the firewall and not in the battery box. By the time we were done monkeying around we were no longer getting power from the ECM. The truck ran and shut off on its own 3 times during the days events.