91 Lumina - how to check codes?

[chris13174]

Amazingly enough, I have had the same exact problem on my 93 lumina and I have tried everything under the sun to fix it. Replaced coil packs, ignition control module, Idle Air Control, MAP sensor, crankshaft position sensor, and have did the idle relearn thing and still the car does not idle clean. My lumina is the 93 3.1L Vin T Engine. I moved onto checking the vacum hoses and did find several vacum leaks but I have now fixed them. According to the chilton books I have on the car, the 3.1 is very sensitive to vacum leaks and repairing the leaks on mine did clean up the idle substantially for a few days, it is now back to the same rough idle and stalling that it originally started doing. What might be the problem here? Would it be worth $24.95 to pay AllData.com in order to see if maybe they have something listed on this problem which seems to be overwhelmingly common amoung these cars?

[Lolamonster]

I have a 1991 Chevy Lumina Apv.
8th letter/number of Vin is a D.
I got a CODE:15 from the OBD1

Could you please tell me what it means?
Thank you

[Stealthee]

15 Coolant Temperature Sensor (Low Temp Indicated)

[Schurkey]

Originally Posted by Lolamonster

I have a 1991 Chevy Lumina Apv.
8th letter/number of Vin is a D.
I got a CODE:15 from the OBD1

Could you please tell me what it means?
Thank you

https://repairpal.com/gm-obd-code-15

You need to TEST the system before replacing parts. This could just as easily be a wire-harness problem as a sensor problem; or even a failed computer.