Corvette176

Hello everyone,

I have a 1999 Corvette Hatchback with Z06 wheels that is getting the reduced engine power message and throwing a couple of codes. Every now and then for the last several months I'll get in the car, start it and I'll start to depress the throttle and get no response until the pedal is half way to the floor. Once the RPMs reach 2000 to 3000 RPM, the check engine light will light up, it will throw P1285, P1125 codes, and a couple of TCS codes. In the last couple of months the only way to get the power back was to turn on the heater on full blast and let it run for 30 minutes to an hour after clearing the codes. The issue would go away for awhile and return at random without warning. Sometimes it would be fine up until I had to go get fuel. After filling the car up, I'd start it and it'd have the same issue where there was no response from the throttle. I have tried everything that I have found so far on the internet with other people having similar issues and I have read most of the threads that I can find on this particular problem.

I've replaced the Accelerator Pedal Position Sensor, the TPS, cleaned the TB, checked the wires to the connections, and I've checked the PCM. Nothing seems to be loose or out of place. That and the fact it will sometimes go away on it's own (mostly when I'm looking at her replacement), but then it will come back up at random. Like last night, I got in it to check something and she had power again (literally after I got back from test driving a BRZ lol), but then the car threw the same codes while driving it a few miles down the street. I wanted to see if the issue would come back. But that was a first, it usually only gave me Reduced Engine Power at start up while sitting still; it's never died while moving.

Though this time was interesting, because aside from the fact it had issues while driving, it gave me a service vehicle soon, check Tire Pressure Monitoring System on the DIC with the usual APPS/TPS codes and the reduced engine power. I pulled up tire pressures on the DIC and one of them had an xxxx on it, which I have never seen before until now. Once I stopped and reset the codes everything went back to normal. The TPMS message has come up before, but it's usually gone away. Though, it's possible I just never noticed it. While typing this I actually just came across a thread about another Vette owner talking about his Active Handling activating because of a faulty TPMS sensor. So I guess, I have two questions at this point. Can a faulty TPMS lead to APPS/TPS reduced engine power issues? And if that's not the issue, can anyone suggest something else I could try to fix it?

Oh and there is one thing that is odd, the Z06 Wheels don't have anything that resembles a TPMS sensor. Is this normal? They were put on by the last owner.

Thanks for the help!

Bill Curlee

The very next time that you get the weird symptoms and ( need to run the heater to clear the issues) "WITHOUT TURNING OFF THE IGNITION" clear any messages in the DIC by pressing and holding the reset button and then READ and post ALL the DTC that are in the system.

Sometimes the car needs to be in DISTRESS to get the rear DTCs that are causing the issue.

Bill

Corvette176

Thanks for the help guys. I cleaned out the grounds I could find and the issue went away for around a week. Then as I was getting fuel yesterday, it did it again. I'll try the others now. But thanks for the information. I appreciate it.

And Bill, I'll try that as well when I get home from work today. Thanks!

Ronnie_W

I know this is old but would like to know if you found what was causing the problem. I have the same intermittent problem with the throttle not responding until about half way down. It went away last time I was troubleshooting the problem but came back again last night.