Service Engine Light/Cooling Fans
Thread Starter
5th Gear
Joined: Apr 2011
Posts: 5
Likes: 0
From: NH
Service Engine Light/Cooling Fans
I have a 1994 Corvette LT1. What is happening is that the two cooling fans come on very early and coincide with the Service Engine light coming on. If the fans shut off so will the light, but for the most part the light and fans remain on.
I have changed the thermostat as well as the temperature sensor in the thermostat housing and the one in between cylinders 6&8. None of this has helped. Even if I disconnect the two relays on the fan housing the light still comes on. Could the problem be the ECM itself? I have even tried to short out terminals A&B on the OBD plug but get nothing, not even the code 12 that is supposed to flash first
I have reached a point where I may have to take it to the dealer to diagnose.
I appreciate any comments.
Thank you.
I have changed the thermostat as well as the temperature sensor in the thermostat housing and the one in between cylinders 6&8. None of this has helped. Even if I disconnect the two relays on the fan housing the light still comes on. Could the problem be the ECM itself? I have even tried to short out terminals A&B on the OBD plug but get nothing, not even the code 12 that is supposed to flash first
I have reached a point where I may have to take it to the dealer to diagnose.
I appreciate any comments.
Thank you.
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
You are on the right track checking for codes, but your 94 is different than earlier cars with the 12 pin ALDL , see this link for the correct pins used to retrieve codes.
http://www.digitalcorvettes.com/foru...56&postcount=9
Understand that many DTC's will cause the fans to run by default once the code sets, the fault does not have to be anything related to the temp sensors or fan circuits.
Once you retrieve the codes post here for assistance or troubleshoot using book #2 of the correct Factory Service Manual.
http://www.digitalcorvettes.com/foru...56&postcount=9
Understand that many DTC's will cause the fans to run by default once the code sets, the fault does not have to be anything related to the temp sensors or fan circuits.
Once you retrieve the codes post here for assistance or troubleshoot using book #2 of the correct Factory Service Manual.
Thread Starter
5th Gear
Joined: Apr 2011
Posts: 5
Likes: 0
From: NH
Thank you, shorting #4 & #12 worked. Getting multiple codes.
Module #4 Code H29, Module #9, ERR, Module A, codes H16 and H62.
Reset codes but they came right back.
Also tried to reset the ABS/ASR (light is also on) but it would not go to 9.7 on the Trip/ODO step.
Suggestions?
Module #4 Code H29, Module #9, ERR, Module A, codes H16 and H62.
Reset codes but they came right back.
Also tried to reset the ABS/ASR (light is also on) but it would not go to 9.7 on the Trip/ODO step.
Suggestions?
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
My suggestion would be to troubleshoot the PCM code first, once you get the check engine light to stay off tackle the ABS issue.
Good information on that subject can be found here.
http://www.corvetteactioncenter.com/...abs/index.html
DTC 29 seems to be related to the Air Injection Pump, there is a fuse, relay and bypass valve in the circuit. Without the correct Factory Service Manual there is little you can do to isolate the problem except to check all fuses with a test light, do it with the engine running as many circuits only have power when the key is in the run position, good luck.
Good information on that subject can be found here.
http://www.corvetteactioncenter.com/...abs/index.html
DTC 29 seems to be related to the Air Injection Pump, there is a fuse, relay and bypass valve in the circuit. Without the correct Factory Service Manual there is little you can do to isolate the problem except to check all fuses with a test light, do it with the engine running as many circuits only have power when the key is in the run position, good luck.
