Problem with my 2002 Chevy Cavalier. 2.2L four cylinder. Question = I have a 2002 Chevy Cavalier that had an inoperable charging system. I replaced the alternator and the battery and there was no change. I soon found out that the alternator was not getting it's start signal from the PCM.
I know this because I saw a diagram on the charging system and the red and gray wire that make up the connector come straight from the PCM. The red one is the alternator start signal wire! The car ran perfectly other than the charging problem before I disconnected the PCM plugs to do a continuity test on those 2 wires. I reconnected the PCM and then reconnected the battery and now the car won't even start. Did I somehow fry the PCM by disconnecting it and plugging it back in?? The car does everything normally except start!!!! Please help?
Answer: It is very possible you damaged the PCM if you disconnected it and did the test with the key on. Or possibly you may have damaged a few of the terminals in the connector or on the computer. Remove the connector and inspect the terminals very closely. Also, be sure to check all the fuses. If all is OK, then sounds like the PCM is bad. You would need a scanner to read alternator cycling data to confirm this.
1996 Chevy Monte Carlo 3.1 v6 Warning lights = volts. Replaced alternator and battery. Question = i am not receiving power to the wire that plugs to my voltage regulator and do not know where it leads so i can test further none of the fuses i can check are blown. I need help.
Answer: The PCM (computer) supplies voltage to the internal alternator regulator on the small red wire at terminal L. You either have a break in that wire or a faulty computer.
You would need to first get a schematic and do some electrical testing to check for continuity between the alternator and computer. Also a scanner to see if the PCM is trying to turn that wire ON.
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