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View Full Version : PCM Losing Parameters



KillianDempsey23
07-23-2021, 04:56 PM
Hey Y'all,

I need some help. I have an 04 Escalade with the 5.3 Vortec and a 4L60E transmission. About a month ago, shortly after I bought it, I noticed an issue where the PCM was losing it's parameters when the key was turned off. The readiness monitors would complete their tests while driving, then when the car was turned off they'd all go back to "INC".

First I checked the wiring harness pins 20 & 57. Both were getting constant 12v power key on or off. The grounds were good as well. Next I tried swapping in a junkyard PCM that I flashed a clone of the original PCM onto. This didn't solve the issue either. I'm not sure what's left that could be causing this problem.

Additional details: The previous owner did an e-fan conversion. The PCM has been tuned to operate the fans (2 wires running from harness to relays that connect battery & fans). There is also a cold air intake on the motor. Is it possible that the tune is causing this issue?

Thanks in advance for your help!

B52Bombardier1
07-23-2021, 08:39 PM
If the OS that you cloned into your junk yard PCM was bad . . . . you just fed a bad OS into your junk yard PCM. Important question - does pin 20 and pin 57 continue to provide power DURING cranking . . . . ????

Rick