Douglas
New member
I have a 1981 Corvette that the check engine stays on when the key is off. When the engine is running the light is off. Help?
deleosfarm@gmail.com
deleosfarm@gmail.com
check engine light stays on
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Welcome to the Corvette Action Center. Moving your post to the C3 Tech forum for greater exposure...
Antz81
Well-known member
Does it show up fault codes when you check for them?
What are the codes? (If any)
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bill81vette
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Welcome to CAC!!!!
enjoy!!!
enjoy!!!
Wajulia
Well-known member
Do you know if the ECM is still in the car? That is very strange behavior. If you do have an ECM, do you know how to read codes? If so, are there any codes? If not let me know and I will tell you how.
Antz81
Well-known member
Just checked, the warning light is fed from the guages fuse, and grounded via the ecm.
With the ignition off, there should be no power to the light. This could be cause by a few things; a dab ignition switch, a wiring fault, maybe a fault in the alternator as well
With the ignition off, there should be no power to the light. This could be cause by a few things; a dab ignition switch, a wiring fault, maybe a fault in the alternator as well
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Douglas
New member
Don't know what ECM is. And where would the codes show up?
Where would the codes show up at? What is ECM?
Wajulia
Well-known member
The 1981 is the first computer controlled corvette. ECM is the Electonic Control Module, or simply the computer
it is located in the battery compartment behind The driver seat. It will be on the front wall of the battery compartment. It is a silver box about 6" x 8" x 3" with two connectors, each with about 25 wires on it
To read the codes you can short the test connector and it will show codes by flashing the check engine light.
Under the ash tray is the test connector. Turn the key off, short the two pins closest to the driver seat ( a small screwdriver will work). Turn the key to on ( not start) and the check engine shoul blink a 12. A 12 would be one blink, pause, two blinks, long pause, it will repeat 12 three times. Then the next set of codes will be the error codes, each one blinking three times, then it will finish with a set of 12's again.
If it does not blink 12's check to see if it is getting power, then it is probably toast
Just curios, is the car running ok, what about the gas mileage, it the ecm is not working the cat will start to get about 10 mpg
it is located in the battery compartment behind The driver seat. It will be on the front wall of the battery compartment. It is a silver box about 6" x 8" x 3" with two connectors, each with about 25 wires on it
To read the codes you can short the test connector and it will show codes by flashing the check engine light.
Under the ash tray is the test connector. Turn the key off, short the two pins closest to the driver seat ( a small screwdriver will work). Turn the key to on ( not start) and the check engine shoul blink a 12. A 12 would be one blink, pause, two blinks, long pause, it will repeat 12 three times. Then the next set of codes will be the error codes, each one blinking three times, then it will finish with a set of 12's again.
If it does not blink 12's check to see if it is getting power, then it is probably toast
Just curios, is the car running ok, what about the gas mileage, it the ecm is not working the cat will start to get about 10 mpg
Last edited:
Antz81
Well-known member
As well as checking the above, (unless you try this first and the light goes out)
unplug the connector from your alternator with two wires in it (one red, one brown). Leave your ignition off when you do this. If the light goes out the problem is in the alternator. If it stays on it's somewhere else.
unplug the connector from your alternator with two wires in it (one red, one brown). Leave your ignition off when you do this. If the light goes out the problem is in the alternator. If it stays on it's somewhere else.
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