Hey guys.

Yep, I have done a search! Most code 53 threads deal with cars that have fuel injections.

I have an '86 Trans Am with the carb (LG4). My car is showing a code 53 and my first thought was a bad voltage regulator. So, I got a new one, then got lazy and ordered an AC Delco rebuilt alternator. That didn't fix things.

This past weekend I replaced the computer. That was an awesome move! My car was running like crap, and now it is smooth and accelerates faster than a 4-cylinder SUV. Awesome. I thought everything was golden until I used the car to commute to work this morning.
Check engine light came back on; code 53. This code doesn't pop up until I have been driving for over 30 minutes or so. Short trips around town never seems to trip it. I do have the EGR unhooked, but not sure that has anything to do with it.

Where else can I look? Freaky battery, maybe? I have a Duracell. The underside is really clean, so no rusty ground connections. Wiring to the alternator is clean and snug.

I have run out of ideas, so looking for any suggestions.

Thanks!
Tony

 

Code 53 on CCC f-body's is usually an EGR malfunction. Which in your case is likely true as it only trips on highway cruise mode.

And, since EGR is disabled...

RBob.

P.S. note that the malfunction codes vary across the different induction systems. Ones for a TBI and TPI engines aren't always going to match up. Let alone match up with a CCC system.

 

For future reference:

RBob.

 

Thanks! I was thinking about the EGR. Not sure how to dummy it up, so I'll take a look at the wiring diagram.

Thanks for the PDF, too!