BAC RV Club Forum
General Boards => Technical Support => Topic started by: John Demartini on October 14, 2026, 07:54:30 PM
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Good afternoon:
My saga with the PAC brake being inoperative continues. I'm almost certain it's in the ECM settings. Current shop is seeking interactive software to access setting changes.
Question: Can anyone confirm that the original ECM on Cat's are painted yellow upon engine final assembly? Mine is black plastic, and I suspect it's been replaced at sometime in the past.
Thank you...
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John
I believe you are correct the ECM would have been installed on the engine along with the wiring harnesses and the whole assembly would then have been painted.
To confirm this you should see the ECM engine harness and plug is painted yellow
To confirm that the ECM you have is a replacement using a Scan tool you should be able to see the Engine serial number as well as the ECM serial number
Then have locate Cat dealer check to verify its not the original.
If it is a replacement it is possible it is not programmed properly for your application.
Does the exhaust brake work at all , what symptoms do you have.
Eric
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John
To my knowledge the only scan tool software that
Will allow parameters changes or programming is the Cat ET. a proprietary piece which has a hefty subscription fee making it almost dealer only.
Eric