C5 corvette “reduced engine power” issues
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5th Gear
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C5 corvette “reduced engine power” issues
I made a post on this recently, but I have a 1997 corvette and lately I get a “reduced engine power” notification on my dash. The temp gauge goes up and my gas gauge goes all the way down and my car just refuses to start, I figured out it was the coolant temp sensor so I replaced it and it started working normal again, but two weeks later my car did the same thing so I used my warranty to replace it again and again same thing happened. I assumed it was maybe the fact that I got a cheap one so i spent $40 on one from ac Delco. Like expected tho after a couple of days it does the same thing a day or so later. Not sure what to do now. Is it wiring what is it? Should I have flushed the coolant before doing this? Because I didn’t flush the coolant and some think I should have
Last edited by standardalias; May 24, 2025 at 01:26 PM.
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From: Cape Coral, Florida
If a bunch of DIC messages, ECT maxes out, gas gauge goes to E and power windows may not work you may have a serial data issue….I don’t know if you have any electrical experience but you can follow the steps below…best to have a scan tool or even a code reader to be able to communicate with the PCM.
1) Locate the 2 Star Connectors to the left of the BCM and remove the buss bar or “comb” from star connector #2…it has 4 wires on it…see if the car starts…if no start go to next step.
2) Now remove the comb off the other star connector leaving both combs removed…make a jumper wire and jumper the BCM to PCM…light green to dark green wire….if car starts you have a module other than the BCM and PCM on star connector #1 pulling the data bus down….if car still doesn’t start the module pulling the bus down is either the BCM or PCM…go to next step.
3) Take your jumper wire and connect from the purple wire (data bus wire) to the PCM (dark green wire)…now with your scan tool see if you can communicate with the PCM…if you can now communicate the PCM is good and issue may be the BCM…to see if the BCM is indeed bad take the jumper wire and connect the jumper now to the BCM (light green)…with a scan tool that can communicate with ALL modules (NOT a code reader) and if you can’t communicate we can “assume” BCM is bad…for single module “no comm” you want to check the powers and grounds to that module.
https://www.youtube.com/live/f_NEEdg...tgrN__-plR_RHU
1) Locate the 2 Star Connectors to the left of the BCM and remove the buss bar or “comb” from star connector #2…it has 4 wires on it…see if the car starts…if no start go to next step.
2) Now remove the comb off the other star connector leaving both combs removed…make a jumper wire and jumper the BCM to PCM…light green to dark green wire….if car starts you have a module other than the BCM and PCM on star connector #1 pulling the data bus down….if car still doesn’t start the module pulling the bus down is either the BCM or PCM…go to next step.
3) Take your jumper wire and connect from the purple wire (data bus wire) to the PCM (dark green wire)…now with your scan tool see if you can communicate with the PCM…if you can now communicate the PCM is good and issue may be the BCM…to see if the BCM is indeed bad take the jumper wire and connect the jumper now to the BCM (light green)…with a scan tool that can communicate with ALL modules (NOT a code reader) and if you can’t communicate we can “assume” BCM is bad…for single module “no comm” you want to check the powers and grounds to that module.
https://www.youtube.com/live/f_NEEdg...tgrN__-plR_RHU
Last edited by C5 Diag; May 24, 2025 at 01:40 PM.
