PCM issues?? Help
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Registered User
Joined: Jul 2017
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PCM issues?? Help So I've done a lot of searching and come up with nothing.
I have a 97 Lt1 firebird. I've been chasing an issue with random misfire.
Fixed the misfire but wanted to reset codes without a scanner.
I read about some kind of pcm reset.
By turning the key on and pulling PCM ignition and battery fuses so I tried this.
Put the fuses back and I got a slight spark sticking in the 2nd fuse.
car won't start at all now
car ran fine previous to resetting codes.
security light isn't flashing and goes off a few seconds after the ignition is turned on.
i can hear the fuel pump and I checked a bunch of fuses to make sure nothing else blew for some reason.
I have a 97 Lt1 firebird. I've been chasing an issue with random misfire.
Fixed the misfire but wanted to reset codes without a scanner.
I read about some kind of pcm reset.
By turning the key on and pulling PCM ignition and battery fuses so I tried this.
Put the fuses back and I got a slight spark sticking in the 2nd fuse.
car won't start at all now
car ran fine previous to resetting codes.
security light isn't flashing and goes off a few seconds after the ignition is turned on.
i can hear the fuel pump and I checked a bunch of fuses to make sure nothing else blew for some reason.
TECH Regular
Joined: Apr 2013
Posts: 456
Likes: 5
Wow... When all else fails, disconnect the battery in full, wait 30 minutes to an hour, hook it back up properly, positive in first and then the negative, see how the car does after.
When you had the ignition power on and you pulled the fuses, it may have disrupted/shorted something out. From my reverse logic, cut the power, that being the battery, reset the PCM, and see what happens after.
I shorted out the interior lights in my car one time touching metal to one of the dome light contacts. The fix turned out to be using a fuse of higher rating to regain the power to that circuit, and then put the proper fuse back in. This came from a buddy of my father's who works on LT1/LS1 Firebirds and Camaros, and the man was right!
When you had the ignition power on and you pulled the fuses, it may have disrupted/shorted something out. From my reverse logic, cut the power, that being the battery, reset the PCM, and see what happens after.
I shorted out the interior lights in my car one time touching metal to one of the dome light contacts. The fix turned out to be using a fuse of higher rating to regain the power to that circuit, and then put the proper fuse back in. This came from a buddy of my father's who works on LT1/LS1 Firebirds and Camaros, and the man was right!
After a tune, I have had the PCM go into a frozen state where the car would crank and not start, I would pull the PCM fuse, turn the ignition on and wait for at least 10 seconds for the security check, turn off the ignition, plug the fuse back in and the car would start every time..but when you did this with the ignition still on you probably blew another fuse somewhere, I dont believe this would have caused the PCM to brick..
