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- - how to reset PCM (https://www.hummerforums.com/forum/hummer-h3-17/how-reset-pcm-47455/)

Justinh

10-14-2023 05:38 PM

how to reset PCM

I've read on this forum that removing power from the PCM is not enough to reset it. So then how is it done? Is it possible to get the adaptive learning values back to default?

hummerz

10-14-2023 07:50 PM

Quote:

Originally Posted by Justinh (Post 404425)

I've read on this forum that removing power from the PCM is not enough to reset it. So then how is it done? Is it possible to get the adaptive learning values back to default?

Disconnect battery cables, after disconnect, jump in with KOEO, use controls: headlights ON position, turn signals ON position, step on brake pedal so lights are in the ON position, radio/hvac/shifter/door lock/windows etc to drain residual power, take your time and wait until you get to 0.00v.

Justinh

10-15-2023 08:10 AM

0V where, across the battery cables?

hummerz

10-15-2023 04:31 PM

Quote:

Originally Posted by Justinh (Post 404430)

0V where, across the battery cables?

0.00v @25

https://cimg9.ibsrv.net/gimg/www.hum...dc77c82128.jpg

Justinh

10-16-2023 07:16 PM

Thanks.

Doc Olds

10-17-2023 08:58 AM

You cannot "reset" a PCM. You can reboot it, but it will retain the last 300 ignition cycles, power or no power.

The only way to change what is in the PCM flash based memory is to over wright it.

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