Working on an 02 MC SS. Had an intermittent no crank issue. Solenoid would click, but starter would not engage. Starter was replaced one week ago. Still intermittent no crank. Troubleshooting it today.

What I've done-

-Tried switching from Park to Neutral, no difference. Elminates P/N switch.
-Verified battery voltage everywhere it needs to be. Tested and cleaned all connections. Checked resistance/voltage drop.
-Removed starter today and bench tested. It is good.

Had my brother crank the car. Solenoid would just repeatedly click, and then smoke under the hood appeared. Pulled the engine cover off and found what is posted below. WHAT does this wire go to? I am having no luck. The RED/BLACK wire burned itself up so it is getting some high amperage and whatever it is, it is not allowing the starter solenoid to hold in and activate the starter motor.

I also jumped the B+ terminal and the S terminal on the solenoid trying to get the starter motor to work. Nothing. But when I did this the burned up wire moved so there is current passing through it.

I am at a loss. Anyone have any idea what this is?

 

Anyone have any input? That RED/BLK wire is a low reference signal from the ignition module to the PCM.

 

Can you smell anything burning? Like electrical?

 

Yes, if you hold the key to START the starter solenoid clicks and that RED/BLK wire moves from current flow and it gets hot and will burn the insulation off if held long enough. I am wondering if some sensor shorted to the low reference wire and is pushing all that current flow through it, but it would blow a fuse and why is it not allowing the starter motor to engage? Unless that short is pulling that much current and not allowing enough for the starter solenoid hold-in winding to function, but that would be A LOT of current. Also wondering if something in the PCM is burnt up since apparently the PCM uses this low reference wire as a "clean ground" signal.

Might be a job for the GM techs to figure out.

Also wanted to add I thought maybe the ICM module had shorted itself internally to this low ref signal and that was the problem. I replaced the ICM last week due to a TERRIBLE phantom misfire and the ICM was the culprit. So I swapped the new one with the old one but it didn't make any difference, still no crank.


I need to do more reading on this low reference signal.

See attachment below as to what wire is heating up.

 

If you hooked up the solenoid to a direct power source and it still didn't crank, my guess would be either you have a bad starter, or your battery isn't cranking enough juice.

Try a different battery first, see if you can borrow one or have a parts store do a test on it.

Secondly take the new starter back and get a new one, you could have bought a dud from the factory.

If you pull the starter off and hook it to a battery it should engage, if you do this and it doesn't engage with power then your starter is toast. This would be your easiest test, well not easy because you have to pull the starter, but you get the point.

When my car was doing that same thing last fall, it would intermittently not start, just click when I turned the key, leave it for a while and then it would work, it was the starter.

 

No it does crank when removed from the vehicle and hooked up to the vehicle's own battery.

The starter is good. I proved that yesterday when I bench tested it using the own vehicle's battery.

Everything in the starting circuit is functioning if the solenoid is working.

What boggles me is why this burnt up wire is affecting the starter or if it even is and I dont have another issue.

Anyone have any luck with the Ask a GM tech website where you only pay if you are happy with the answer?

 

Might I ask - is the motor seized?

Been there.

 

Nope.

The starter MOTOR does nothing when in the vehicle starting circuit. The solenoid functions, and as the key is held to the START position, the RED/BLACK low reference wire to the PCM becomes very hot.

With starter bolted to the vehicle and connections hooked up, turning key to the ON position and jumping the S terminal to B+ on the starter, the solenoid works but the starter motor DOESN'T. This also causes the RED/BLACK wire to move (due to extreme current flow, I suppose. My brother claimed the wire moved when I jumped the terminals).

Unbolt the starter from the vehicle and hook it up to the vehicle's own battery (used battery jumper cables) and then jump starter B+ to S terminal and the starter motor works as it should.

I'm lost.

 

Fixed a few weeks ago.

Bad ground from negative cable to the engine block near the trans bell housing. It is located almost directly above the starter motor.

 

Great to hear - thanks for the update