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HP Tuners and Cummins 5.9L (2006)

Practical Diesel Tuning

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Discussion and questions related to the course Practical Diesel Tuning

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Hi Everyone!

Has anyone run into ECU lockouts after 4-5 writes using HP Tuners? Not making swinging changes to timing or fuel, mostly code changes with the addition of an aftermarket trans. Things start off ok, and after 4-5 writes, I've gotten locked out of the ECU entirely. After the first lockout, got another stock ECU from the junkyard, switched to a shorter, more robust USB cable, and after the 4th write, blam! Locked out again! Stand-alone reader won't read codes either. Has this happened to anyone else or am I just that unlucky?

There may be some electrical gremlin on the truck that is bouncing you during the read. I'd first recommend hunting down and disabling any aftermarket electronics. Second, most Cummins ECU's are recoverable using a process called 'ROM Boot'. You may need to buy some harnesses etc. to use the process but it's probably cheaper than committing CM849's to paper weight detail.


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