Bad PCM?
Thread Starter
Teching In
Joined: Nov 2022
Posts: 16
Likes: 19
Bad PCM? Hey all, just want to confirm I’m not misdiagnosing.
P0758 Shift Solenoid B
4L60E
I started at the transmission and replaced the solenoids without much thought and serviced the transmission and confirmed nothing was wrong. But it was open so I went ahead and installed new solenoids. Ohm readings where ~22ohms on both the old and new, and when applying voltage I can hear them click.
Moving back I inspected the connector terminals E, A, B. They appear to have a good connection and no bad pins. E has good voltage (key on) and with my HP scanner I commanded 1st-4th and verified I’m fitting no ground signal to pin B.
so wiring fault or pcm, I checked the PCM terminals (Red 47, 48) with the plug on and off, and I have the same issue. No signal.
as a separate but similar issues, the Alternator terminal L stays on consistently.
my thoughts are to replace the pcm, and unfortunately reflash $$ the tune.
opinions?
thanks,
~Cam
P0758 Shift Solenoid B
4L60E
I started at the transmission and replaced the solenoids without much thought and serviced the transmission and confirmed nothing was wrong. But it was open so I went ahead and installed new solenoids. Ohm readings where ~22ohms on both the old and new, and when applying voltage I can hear them click.
Moving back I inspected the connector terminals E, A, B. They appear to have a good connection and no bad pins. E has good voltage (key on) and with my HP scanner I commanded 1st-4th and verified I’m fitting no ground signal to pin B.
so wiring fault or pcm, I checked the PCM terminals (Red 47, 48) with the plug on and off, and I have the same issue. No signal.
as a separate but similar issues, the Alternator terminal L stays on consistently.
my thoughts are to replace the pcm, and unfortunately reflash $$ the tune.
opinions?
thanks,
~Cam
TECH Fanatic
Joined: Dec 2017
Posts: 1,477
Likes: 271
From: Bossier City, Louisiana
You could go to the junk yard and buy a new PCM for $40.00 and then flash it yourself with the free tuning tools - Tuner Pro RT, PCM Hammer and / or LS Droid. Do you have a thumb drive copy of your last known good PCM operating system? Its a good idea, for times like this.
Rick
Rick
Thread Starter
Teching In
Joined: Nov 2022
Posts: 16
Likes: 19
You could go to the junk yard and buy a new PCM for $40.00 and then flash it yourself with the free tuning tools - Tuner Pro RT, PCM Hammer and / or LS Droid. Do you have a thumb drive copy of your last known good PCM operating system? Its a good idea, for times like this.
Rick
Rick
I’ll have to look into getting started with pc hammer. I have copies of my tune, but I’ll need to look into file compatibility too since they where saved with HP
Thanks,
~Cam
TECH Enthusiast
Joined: Jul 2019
Posts: 638
Likes: 187
Aside from the software, this is what I was planning. I really just wanted to play sounding board to make sure I’m not missing or overlooking something.
I’ll have to look into getting started with pc hammer. I have copies of my tune, but I’ll need to look into file compatibility too since they where saved with HP
Thanks,
~Cam
I’ll have to look into getting started with pc hammer. I have copies of my tune, but I’ll need to look into file compatibility too since they where saved with HP
Thanks,
~Cam
