99 Grand Am Engine fixed, wont shift now

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Aaron1100us

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I replaced the PCM, coil, ignition module, new plugs and boots. Engine runs great but it wont shift out of 1st gear while in drive. And the security light is on.
 
anyone have this issue before
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What prompted you to replace the PCM, the new one does not recognize your ignition key. The other issues may also be related to the PCM, did you get the correct one and is it programmed for your car?
 
Correct PCM. Number match but it was from an Alero. Guessing that it just needs to be programmed. The old PCM was bad, not sending a signal to #4 injector. Engine runs great now, just the tranny and speedometer issues now.
 
Have an appointment at the dealership tomorrow to have it programmed. Hope thats all it is. $125. I have a lot of $$ in this car, hope it fixea it. Atleast the owner is ok with the prices. IMO, way toouch $$ to sink into a junky car.
 
^^ you've been working on this car for someone? Sounds like you replace many things that were not yet due.

I replaced the PCM, coil, ignition module, new plugs and boots. Engine runs great but it wont shift out of 1st gear while in drive. And the security light is on.
Click to expand...

Coils, ICM, wires, and spark plugs maybe not have needed to be replaced atm. IDK how much you spent or anything but fixing an older car is often cheaper than buying a new one.
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Well, it needed a tune up so thats why I did the plugs and boots. When I first put my scanner on it, it said that it had a faulty injector on #4. So I put in a new injector. Still got a #4 injector code. Checked wires and they were fine. From there, I knew the PCM controls each injector. Put in a used PCM. After that, no more injector codes. Car started but still missing on #4. New injector,PCM,good fuel pressure, good compression yet missing on #4. You need air/fuel mixture, compression, and a spark to run. Thought the fuel side was fine. Put a noid light on #4 and it was flashing which means the new injector was getting a good signal.

You would think a new injector, good fuel pressure and a good signal from the PCM would mean the fuel side was good right?

Fuel side good and compression good. That leaves the ignition system.

New plugs and boots. That leaves the coil and ICM (just because it all comes together). Plus I tested the spark on #4 and it seemed like a weak spark. A weak spark might not ignite the air/fuel mixture.


So I got the coil and ICM. Still missfire on #4. Thats when I had the idea to ohm the other injectors and compare them to the new injector. A new injector should not be bad but I tested it anyways. It was out of range compared to the three other injectors.

PCM was out of an Alero so its not communicating wih the BCM and TCM correctly. Should be fine after it gets programmed to this vehicle. I surr hope so.
 
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