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I had my C5 convertible with a manual transmission out last night and it ran perfectly. Parked it in my garage overnight. Went to leave this morning. It started right up and appears to be running well, except that when I press down on the accelerator pedal the engine continues to idle. My oil pressure sensor has been bad for months, reading 80 psi on the gauge and 120 psi on the DIC. Now the DIC displays "Reduced Engine Power", "Service Traction System", and "Service Active Handling".
Corvette has 86K on the odometer.
A0-LDCM 3 CODES
A1-RDCM 3 CODES
A6-SCM NO CODES
B0-RFA 7 CODES
10-PCM 1 CODES
28-TCS NO CODES
40-BCM NO CODES
58-SDM 1 CODES
60-IPC NO CODES
80-RADIO NO CODES
99-HVAC NO CODES
I can't move the car now even though the engine sounds fine. I appreciate any input that could help me diagnose the problem before I have to get it towed to a shop.
Thank you!
Last edited by rbritland; Jul 16, 2020 at 04:55 PM.
Reason: make additions
First check fuse 17 ( throttle control) and make sure it is not blown !!....also what is the PCM code you are seeing ??...you may a few issues going on there !!
I believe 1518 is TAC module serial data circuit...for now replace the fuse and we will see if it blows again !!...serial data circuit is the circuit that allows communication between all the cars modules...PCM, BCM, EBCM, etc...another thing is make sure you have a good battery !!
Well I don’t know if you are going to try the diagnosis but you will need to access the TAC module which resides next to the PCM...remove the harness that has a pink wire in it...it’s Connector C2 Pin 7...I don’t have the connector view in front of me but I think it may be the larger connector of the two...you may have a short to ground on that wire from the fusebox to the harness or a bad TAC module...if you replace the fuse and remove the connector and with key on the fuse blows again the wire may be chaffed somewhere...if it doesn’t blows sounds like a bad TAC module !!..some pictures below.
Had those oil pressure readings on my 2000 and the oil pressure switch was bad. Not related to the other problem you are having as my car ran fine. Chevy dealer wanted 800 bucks to replace the switch but I replaced it myself for the price of the switch about 70 bucks. Good luck with the other problem.
Where on the car is the PCM and TAC module located?
You will have to remove the right front (passenger) side tire...this video should help !!...you can see the TAC Module attached to the front of the PCM !!
I disconnected the connector with the pink wire at C2 pin 7. I replaced the fuse again and started the engine. Turned off the ignition and checked the fuse. The fuse did not blow this time. I removed the TAC no. 25311783. I found a used replacement TAC on eBay for $300. Is this the best way to go? Do you know of a better place to get a replacement TAC? You have been a great help, much appreciated!
Anytime you order from EBay you’re always taking a chance but I don’t know if these sellers offer refunds especially on electronics... glad you got it diagnosed...good job !!
I could not find a 2000 Corvette TAC model number 25311783 anywhere except used on ebay. Apparently they are no longer available from GM or anywhere else new. I purchased a used one on ebay for $276.25. It was delivered yesterday so I plugged in the two cables and started the engine. Codes disappeared and I could rev the engine. I put everything back together and went to move the car, but the engine would not rev and all the codes came back. Checked fuse #17 and it's blown again! Now what?
Could the problem be in the pedal? I'm at a loss and I can't move my car. Even if I have it towed to a Chevy dealership for service, how can they repair it if parts aren't available? Is a beautiful C5 Corvette convertible with 86,000 miles only good for a parts car? PLEASE HELP!
Last edited by rbritland; Jul 23, 2020 at 12:33 PM.
Reason: make additions
WOW !!...so a new TAC Module didn’t fix it ??...not knowing how the internals of the Module is wired led me to this diagnosis...the TAC module is fed power on a pink wire from the fuse 17...the only pink wire I see is on the TPS sensor is the TPS 2 signal wire which is pink but the circuit numbers are different...you can try unplugging the TPS sensor, the APP Sensor or the TAC motor...it may be one of these.
Thank you for getting back to me. I plugged in the replacement TAC and tried it and it worked. Then I put the inner fender and tire back on, but when I started the engine it blew the #17 fuse and wouldn't work, accelerator pedal did nothing. Very frustrated, went to bed but couldn't sleep. Went out to the garage this morning to take it all apart again. Thought I'd give it one last try. Replaced fuse #17 again, started it and it's working! Took it out of the garage, turned it around and put it back in the garage. I haven't tried to drive it away from the house for fear I'll get stranded. It's like an intermittent problem. Tomorrow I'll take it around the block a few times, if it goes that far. If it keeps working, I'll have to build up my confidence in the car once more before traveling. If it fails again, I'll try your lastest suggestions. You still have not given me a suggestion as to where I can buy a NEW TAC. Do you know of anyplace? Again, thanks so much for getting back to me.
I'd try the “wiggle test” while the engine is running....I would concentrate on shaking the wiring at the TAC servo motor and TPS sensor...you may have a chaffed wire somewhere under the hood where there are more vibration...try to follow the wire loom back from both components...I don’t think you can buy a “new” TAC Module these days !!...I’d have to look but I think the servo motor wiring runs behind the fuel rail bracket where a lot of chaffing occurs !!
parts are always available for these cars just because you cant find them doesn't mean the dealer cant. May not be in production but all products can be found one way or another.
So pink is a hot wire right guys ? Anyways pink also goes from the bcm up through into the radio / ignition/fuel door. So I would suspect a open wire blowing fuses . Aftermarket radio Jerry Rigged in there ?
Soon you will find out that open wires can do a number on the fuses . You shouldn’t worry to much about the modules for this year just a heads up. They were designed to blow fuses before modules if your getting the hint check the wires along that fuse line .
Last edited by Speedy007; Jul 24, 2020 at 01:36 AM.
C5 sudden problem
