How Do I Tell If My PCM is Bad

GMAN

GMAN

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My car has been dead for about a week. I thought the PATS was engaging, so I had my SCIL reflashed. It started when I when to the muffler shop to have mufflers put back on the car. When they were done, the car wouldn't start. It has been this way for a week now. I found a blown 30amp fuse for the PCM in the passenger fuse box. I've replaced that, and still no start. I've swapped the relay for the PCM in the engine compartment with the horn relay, and still nothing. One thing I am noticing is when the key is in the run position the CE light is not on. Does this mean the PCM is bad or still not getting power? I don't know where else to look.
 
So you've got no crank?
Do you know how to directly engage the starter?
 
30amp bad fuse after the mufflers were put on? Did the disconnect the battery when they were welding on the car? It's not a must but it is the safe way.
Like sap said, try and jump the starter. If you know how you can check the main ign harness and see if.your key cylinder is bad. Wire colors are in your other thread I posted for you.
 
I've replaced the key cylinders already with my replacement key and SCIL, and I still have the same problem. I am inclined to believe the problem is not with the starter and with the PCM. The CE light is supposed to stay on when the key is in the run position. Right??
 
Jack up the right front so you can ground out the solenoid on the starter with a long handle screw driver, have key in run. If you do it right it'll spark a little
 
If you blew a 30 amp fuse chances are something is shorting to ground...get the wiring for that circuit and start checking that circuit power probe is your friend...pcms are usually the last thing to fail...it's an interior fuse, you had the dash out...I'd be checking wiring
 
Where is the PCM located on this car?
 
Your PCM is not necessarily bad but for sure it is not being powered up. Be sure to also check the wiring underneath the vehicle. Any harness they could have fvcked up or had a hot chunk of weld land onto for some odd reason. The transmission harnesses under the car would have me curious. That is in the general area kinda :confused: If there is a short to ground in the bulkhead connector on the transmission for example, I know from personal experience that will blow that fuse and cause those symptoms. I know this from personal experience. Not saying that is your issue, but worth a check.


And correctamundo Chris. The PCM is also above the left foot secured vertically behind the e-brake.
 
You also have the main harness running across the front of the back seat under the carpet, at the back of you knees if you were sitting in the back seat. If they welded anything to the floor in that area they could have burnt a wire causing a short.
Just a thought.
 
The were only welding on mufflers, as mine were cut off by the previous owner. They were not in any crucial areas. All the issues electrical wise from the impact I repaired, I think it best that I put in my spare dash and harness.
 
GMAN said:
The were only welding on mufflers, as mine were cut off by the previous owner. They were not in any crucial areas. All the issues electrical wise from the impact I repaired, I think it best that I put in my spare dash and harness.
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Shops can be sloppy. That's all I'm saying. When you have a problem arise right after work was done on your car, that should raise a red flag. Again, I've been through all this. Coincidence maybe. Their fault, very likely. Read your first post again. I would take 97MarkJA's advice also. That is even closer to the vincinity. I'm almost willing to bet a short is the culprit.
 
I found the harness the hard way :(
I went to town the winter.. spring.. oh wait.. still going, while welding in the full chassis stuffing (just like you see on temple's web site) I made the crucial error in not pulling the harness away from the metal with the carpet. It made for a fun hour of wire work, luckily I've done that type of work most of my adult life and I caught it right away. The battery was disconnected at the time and I smelled the wire as soon as it got hot, you know what that smell is right away.
 
As in my other posts, I am confident this has nothing to do with anything that was done at the muffler shop. This has been happening at random, but would usually start after a half hour. So I will put in my spare dash when I get back from vacation.:cool:
 
Did you leave the car out? I wanna come borrow those wheels since you can't get it started anyway
 
Sapperfire said:
Did you leave the car out? I wanna come borrow those wheels since you can't get it started anyway
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hahahahahaha.... what the hell are you gonna put them on and drive? Quit messing around online and get that hood sanded Sapp. I see daily pics of that hood and it is going to be bad ass. You are going to have a hood that is easily worth $1500 or more but ONE OF A KIND!

GMAN, someone on here had a bad PCM, computer, w/e and I sold them one because their car wouldn't crank. It was a Gen 2 and when they got the computer I sold them, the car cranked up and runs fine. Why can you not just swap it for a known good one? It's in here somewhere where I sold it and then him coming back and saying he was now good to go.
 
NoLimit95 said:
hahahahahaha.... what the hell are you gonna put them on and drive? Quit messing around online and get that hood sanded Sapp. I see daily pics of that hood and it is going to be bad ass. You are going to have a hood that is easily worth $1500 or more but ONE OF A KIND!

GMAN, someone on here had a bad PCM, computer, w/e and I sold them one because their car wouldn't crank. It was a Gen 2 and when they got the computer I sold them, the car cranked up and runs fine. Why can you not just swap it for a known good one? It's in here somewhere where I sold it and then him coming back and saying he was now good to go.
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Been there done that. I have three good PCM's and I couldn't get any of them to fire up.
 
G- did you check for 12v at the starter?
If you got power I would blame the solenoid they get baked were they are, my 93 did the random no start strand your ass when the solenoid was shot.
 
i'm having same issue...after i push the unlock button on the remote the slowly blinking anti-theft light stays on...after i put the key in the on position the anti-theft light blinks rapidly with check traction control, gear display error, rpm data error, etc...i turn the key to start and it keeps cranking but doesnt turn over...i plug up the xcal to read if there are any codes and pcm isn't connecting (can anti-theft disable this?) ...battery's full and no blown fuses....tried to ground the dark green/purple wire from SCIL to disarm but all it does is unlock the doors and after trying to start it, it still just keeps cranking and the anti-theft light still flashes rapidly
 
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CobraStar_LS8 said:
i'm having same issue...after i push the unlock button on the remote the slowly blinking anti-theft light stays on...after i put the key in the on position the anti-theft light blinks rapidly with check traction control, gear display error, rpm data error, etc...i turn the key to start and it keeps cranking but doesnt turn over...i plug up the xcal to read if there are any codes and pcm isn't connecting (can anti-theft disable this?) ...battery's full and no blown fuses....tried to ground the dark green/purple wire from SCIL to disarm but all it does is unlock the doors and after trying to start it, it still just keeps cranking and the anti-theft light still flashes rapidly
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Hey cobrastar did you ever figure out what the problem was? Mine is now doing the same.
 
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