DIY GM Gen 3 Bricked PCM Recovery

P01 and P59 PCMs (typically found in 99-07 GM 4.3 V6 and V8 applications) 

P01 Service numbers (red and blue plugs):  09354896 and 12200411

P59 Service numbers (green and blue plugs):

• P59s with idle air control drivers for electric or cable operated throttle bodies:    12581565, 12576106, 12586243, 12589462 and 12602801

• P59s WITHOUT idle air control drivers for electronic throttle bodies ONLY:     12582605, 12586242, 12589463, 12602802

"Bricked" PCMs usually happen due to a failed flashing event, typically vehicle battery voltage goes low, the connection is interrupted, or there is interference from other modules (typically radios, etc).   

If you're getting controller unlocker errors and you haven't even tried to flash it yet, try removing your radio, onstar, and transfer case fuses (if there is one specific for that module).  This is most common on 2003-7 trucks in particular or if you have an aftermarket radio, etc.  

If you did have a failed flashing event, don't turn the key off.  Try the flash again and remedy any of the issues mentioned above.

If you are getting timeout errors after all that and you know there was a failed flash and the vehicle no longer runs, you can try and recover the ECM by forcing it into recovery mode:

NOTE: This is preferably done on a bench harness.  If you have no choice, it can be done in the vehicle, but remedy whatever problem caused the failed flash in the first place.  Fully charge the battery, remove the radio and transfer case fuses, keep your computer's battery charged up fully, etc.

1) Remove the PCM from its bracket so the cover is accessible.

2) Remove the cover by removing the four torx screws and prying it off.

3) Get something metal with a sharp point that you can use to touch a solder pad on the exposed PCM board.  I like to use a multimeter lead with an alligator clip on the opposite end, but in a pinch I've used paperclips, needle nose pliers, a set of keys, etc.

4) Identify the correct solder pad that you will need to ground out.  It is in the same place on both the P01 and P59, though they may look slightly different.  It is the pad next to the two vertical.  Use a marker or paint to help you mark the right one if you can't remember.  First picture here is a P59.

5) Turn the ignition on and get your computer ready to do a full write of the PCM with your known good tune file.

6) Briefly (1 second or so) complete a circuit from the solder pad to the case of the PCM to ground the pin.  This picture is a P01.  NOTE: Some people have needed to hold the pin grounded until the tuning program begins its write routine.  If you have trouble with the momentary grounding, try holding the ground until you see some activity!

7) Start the full write of the PCM.

If you continue getting the same message, remove all power from the PCM for a while and try again.  If it still doesn't work try it on a workbench harness.   If still nothing helps you may have other issues or the PCM is hard bricked.  If you need a cloned replacement I can provide those based on your last tune file to recover your PCM license, just contact me at www.facebook.com/customecm