Lately, I have been getting a code 53 when driving long distances on the highway or interstate. The car still runs fine, but I want to take care of it before it becomes a real problem(not to mention how annoying it is to have that light in your face. This doesn't happen on short trips, or in stop and go traffic. My Haynes manual says that it is a system over-voltage. If this is right, what can I do to fix it. Any help is greatly appreciated. The car is a 1986 firebird LG4 auto.
Cole

 

I would check to see how much voltage the alternator is puting out at the battey. The max it should be is about 13.86 volts. I had the same problem with an LG4 87 formula and replaced the alternator. now I have no problems with the car.good luck wes

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