reduced engine power

[vetteguy61]

I just had all the grounds and connectors checked and cleaned on my 2001 vette. I am still having trouble with the check engine light,service traction control and reduced engine power coming on when I'm stopped or driving. The latest codes to come up were P1221,P1515,C1278. I'm starting to pull my hair out over this problem. Anyone had this problem or can point me in the right direction. Thanks.

[jj2k]

Let me say up front, I'm not a mechanic. Take this for what it's worth. Have you checked your brake system? Here's why I ask. A couple of months ago I got the service traction control light and code as well. Right after that the brake light came on. About 10 minutes later the DIC displayed low brake fluid. I took it in to have it checked and was told the front brakes were shot, the rears were ok. So, new pads and rotors up front and the problem went away. Two months later the same thing happens: service traction control, low brake fluid light. Took it to a different mechanic and he found the master cyclinder needed to be replaced. He did say the brakes were fine all the way around.

So, this could be related to your problem, or it could just be useless info. I hope you get your problem diagnosed and fixed quickly. The things can be quite persnickety sometimes.

[Hib Halverson]

I just had all the grounds and connectors checked and cleaned on my 2001 vette. I am still having trouble with the check engine light,service traction control and reduced engine power coming on when I'm stopped or driving. The latest codes to come up were P1221,P1515,C1278. I'm starting to pull my hair out over this problem. Anyone had this problem or can point me in the right direction. Thanks.

Do you have the factory service manual for 2001?

If you do, have you done the diagnostic procedures listed in the FSM for those fault codes?

If you don't have the FSM, buy one. You'll end up with 1) more hair and 2) advice on how to troubleshoot and repair those problems.

Zip Products sells factory service manuals.

[jvdaniel]

Check this thread that I posted in 2006." Electrical problems, Help "
I found that there was water shorting the BCM. I cleaned it up and haven't had any problems since. Also make sure that you clean out the cowl drains, especially the one right behind the engine, its hard to get at, but if it is clogged, water will run over the BCM. you may not even notice it.

[Pac-man]

Sounds like the problem that I had. It was the plug for the bundle off wires in the passenger door. Male female connector was bad and I had the same codes. Open the door and move the bundle around and you can figure it out.

[gmjunkie]

I just had all the grounds and connectors checked and cleaned on my 2001 vette. I am still having trouble with the check engine light,service traction control and reduced engine power coming on when I'm stopped or driving. The latest codes to come up were P1221,P1515,C1278. I'm starting to pull my hair out over this problem. Anyone had this problem or can point me in the right direction. Thanks.

My guess is you have a faulty TPS (Throttle Position Sensor) the P1515 and C1278 are tripped in the aftermath!Bad News is the TPS isn't serviceable except with Throttle Body Replacement!!
You should probly check for bad connections and broken wires first around the throttle body!My SI service program has 21 steps for diagnostic testing to sort it out!!

DTC P1221

Circuit Description

The throttle position (TP) sensor is mounted on the throttle body assembly. The sensor is actually 2 individual TP sensors within 1 housing. Two separate signal, low reference and 5 volt reference circuits are used in order to connect the TP sensor assembly to the throttle actuator control (TAC) module. The 2 sensors have opposite functionality. The TP sensor 1 signal voltage is pulled up to the reference voltage as the throttle opens, from below 1 volt at closed throttle to above 3.5 volts at wide open throttle (WOT). The TP sensor 2 signal voltage is pulled down to the low reference from around 3.8 volts at closed throttle to below 1 volt at WOT. TP sensor 1 and APP sensor 1 share a 5-volt reference circuit that is connected within the TAC module. TP sensor 2 and APP sensor 2 share a 5-volt reference circuit that is connected within the TAC module. If an out of range condition is detected with the TP sensors, this DTC will set and the Reduced Engine Power message will be displayed.


Hope this helps!~!

[hdboomer]

I had the same problem, car was under ext warr, the dealer replaced the BCM problem is gone, that happened 1 year ago. list price for a bcm is $1160.00 part number is 10304931 labor was $234.00 dealership I saw on this web site sells BCM for $700.00 plus. I paid $100.00.