When the car has no chip/Eprom (and so is running in Limp Home Mode) in it will the Alternator charge the battery and give the car its power? Please say no.

We took the car out in LHM as we needed fuel fast, and didnt realise we had not charge untill it was too late then had to stand about in the rain and nurse the baby home with about 3 jump starts.

Thanks for any advice.

JAmes

 

The ECM has no control over the generator in that year. The gen is fed it's field power thru the red wire on the plug, the "sense" or gen turn on is the other wire in the plug(usually a tan or brown wire). Both should have approx 12 volts with the key on-engine off. The rear wire at the lug feed directly to the battery thru a fuse link. It also should read 12 volts, but it will read it all the time. It is not key controlled due to the high current it feeds to the battery. Later GM CS-130D generators that use the ASVR regulators are PCM controlled and use 5 and approx 2.5 volts for control. They only show up in vehicles after 97 or thereabouts.