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"Check Engine" Light that will not turn off

My friend has a 1996 or 1997 Pontiac Bonneville with over 130K miles on it and its been in her family for several years and she says the “Check Engine” light on it has never turned off. She’s taken it to different shops to have it looked at and none of them can tell her what’s wrong with it. As far as she can tell, the car runs fine, she keeps up with the service on it but I wonder what would be causing this? I once owned a 1999 Chevy Malibu with the V-6 3.1 liter engine and I had the same thing happen to me but when I had it serviced, the mechanic hooked a little code reading device to it and turns out the spark plugs were misfiring so he changed the coil pack in it…problem solved. So obviously my friend is having issues with fuel emissions system in it but I wonder why the mechanics in the City she lives in can’t seem to figure out the problem. Not saying her car has the same problem my old malibu once had, there’s a number of reasons why that light turns on and from what I’ve learned it usually involves the fuel emissions system in it. So what could be wrong with it?

No one can get started without know what the exact error codes are. Many auto parts stores will read these for free (with the little code reading device). Get your friend to take the car to such a place and have the codes read. Tell her just to write down the very exact and specific code. They look like “P1234”

Also ask her to check her receipts from whomever has looked at it and report as much as possible about what has been done to the car. A basic run down of the state of basic maintenance would be good too - age of plugs & wires, filters, cooling system service history etc.

I’ll be sure to tell her that. I don’t know if she’s a particular as I am about keeping service receipts but who knows? I keep all my service receipts mostly so I remember what’s been done to my car and those service receipts come in handy if I ever plan to sell my vehicle and the prospective new owners want to know the history of my vehicle.

Without the codes we can’t even speculate on possible causes. Tell your friend to take he car to an auto parts store for a free code scan. I know most Auto Zone stores do this for free and probably many others, but tell her not to buy parts on the stores recommendation, it may need parts and it may just be a sensor that needs cleaning or a vacuum leak causing the CEL. When she has the codes post them and we can give better advice on what the problem may be. Any real garage should have been able to have pulled the codes and troubleshoot to find the problem. If they don’t know how to do this I wouldn’t be taking my car there for repairs/service.

By finding out the codes we might be able to help her solve the problem, but we can’t make her care. perhaps if you could get her to write iun with the codes we can get started.