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Topic: Check engine light will not go off or flash

in Forum: C3 Electrical

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Re: Check engine light will not go off or flash

Posted: 12/3/13 5:30pm Message 11 of 25
stutrac
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Bethany, CT - USA
Joined: 11/14/2013
Posts: 32
Vette(s): 1981
yes i tried to pull codes and no light flashing i used the last 2 pins on the right side


1981 Vette
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Re: Check engine light will not go off or flash

Posted: 12/3/13 8:35pm Message 12 of 25
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Adams' Apple
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Duncanville, TX - USA
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
If jumpering the A & B pins does NOT cause the light to flash codes, or at least a code 12(meaning no codes stored) with two different ECMs, there has to be a problem in the circuit for the light itself. Ouch




Joel Adams
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Re: Check engine light will not go off or flash

Posted: 12/3/13 9:20pm Message 13 of 25
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rraider1
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Woodland, WA - USA
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Vette(s): 1977 T-Top,350,Auto Black Ruby Pearl,Steeroids R&P conversion

To clarify the question

With the ECM completely disconnected Does the check engine light remain On?

If the answer is yes the problem would be an issue in the BRN/WHT wire from the ECM to the check engine light assembly

If no and you believe the ECM to be good. you would need to look at the wiring to ECM

 





Re: Check engine light will not go off or flash

Posted: 12/4/13 8:30pm Message 14 of 25
stutrac
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Bethany, CT - USA
Joined: 11/14/2013
Posts: 32
Vette(s): 1981
mine is a 5

 (modified large image to link-aapple)




|UPDATED|12/4/2013 8:30:14 PM (AZT)|/UPDATED|



1981 Vette
auto

Re: Check engine light will not go off or flash

Posted: 12/5/13 5:20am Message 15 of 25
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Adams' Apple
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Dangit....that's right.
In that case, you need this diagram....


When you jump the A & B terminals, and turn the key on, you should be able to hear the mixture control solenoid in the carb buzz/click. If it does, it means the ECM is awake, and the Check Eng. light should flash a code 12....one flash, a pause, and two quick flashes. It will do this three times, and then flash any other codes it has stored. Code 12 is just a nothing code..it only means the ECM is in diagnostic mode. If that's the only thing it flashes, it means there are no codes stored.
Then again...if the dadburn light stays ON ...there has to be an issue with the wiring....Cry

CORRECTION! The 5 pin ALDL connector needs the D & E terminals jumped....my bad. Thanks Bob! Embarrassed


|UPDATED|12/5/2013 5:20:14 AM (AZT)|/UPDATED|



Joel Adams
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Re: Check engine light will not go off or flash

Posted: 12/5/13 6:43am Message 16 of 25
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rraider1
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Woodland, WA - USA
Joined: 10/14/2003
Posts: 1171
Vette(s): 1977 T-Top,350,Auto Black Ruby Pearl,Steeroids R&P conversion

I don't want to confuse things but this GM ECM replacement paper says for 81 jumper D E

http://www.C3VR.com/member_pages/4201_4300/4221/ECM-test0001.jpg 

http://www.C3VR.com/member_pages/4201_4300/4221/ECM-test0002.jpg 

http://www.C3VR.com/member_pages/4201_4300/4221/ECM-test0003.jpg 

http://www.C3VR.com/member_pages/4201_4300/4221/ECM-test0004.jpg 


I hope I made the larger for those of us with older eyes






|UPDATED|12/5/2013 6:43:22 AM (AZT)|/UPDATED|



Re: Check engine light will not go off or flash

Posted: 12/5/13 5:20am Message 17 of 25
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Adams' Apple
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Duncanville, TX - USA
Joined: 11/8/2003
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
 Embarrassed Thumbs Up


Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: Check engine light will not go off or flash

Posted: 12/5/13 4:46pm Message 18 of 25
stutrac
Former Member
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Bethany, CT - USA
Joined: 11/14/2013
Posts: 32
Vette(s): 1981
so am i to assume i jump the 2 on the left NOT the right to get the codes?


1981 Vette
auto

Re: Check engine light will not go off or flash

Posted: 12/5/13 8:19pm Message 19 of 25
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Adams' Apple
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
 

Here's what you need to jump... The black/white wire, and the White/black wire....Thumbs Up

 


Joel Adams
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My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: Check engine light will not go off or flash

Posted: 12/6/13 8:35pm Message 20 of 25
stutrac
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Bethany, CT - USA
Joined: 11/14/2013
Posts: 32
Vette(s): 1981
Thank you for the help everyone i got a code 15 coolant temp sensor, i see a few sensors on the block? location.


1981 Vette
auto

in Forum: C3 Electrical


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