Hello all! I just purchased a 2006 c6 with a cam install and other mods...( cai, long tubes, no cats, xpipe, route 66 exhaust. ) when I picked it up it wouldn't start and had to wait and try again. Started and got it home but after about 10 starts i would have to pull neg. to reset. Got worse and worse. I was assured that it was running fine until it was power washed ( outside only), but may have got water throught side vent unto PCM. It was under warranty. I Got a new PCM and got it re-tuned. Now it drives great, and is very strong, until you turn the traction control off. Then engine light comes on, reduce power mode and throws the p1516 code along with p0606. The first code is throttle body is off. I checked the wires at it all looked good. No breaks or loose. the last code is bad PCM I think. I find it highly unlikely that 2pcm are bad. Please anyone point me in the right direction. I have searched the forum but haven't found anything like this. Most people get the traction control warning, as I don't. Just reduce power and have to check the codes. Thanks for any input.

 

So you have two codes that show up. P1516 could be either the Throttle Body, the TB connector, the wiring, the ECM or the ECM connectors/pins. P0606 could be the ECM or the ECM connectors/pins. Lets use some logic here. The car first had a problem with the ECM or its connectors. If you can believe the person, somebody in the know said the problems didn't occur until the car had been power washed (a used car clean up guy???). Replacement of the ECM seemed to fix it.

The Traction Control button is supposed to be wired to the BCM which then sends a message across the data link to the EBCM telling it whether or not TC has been turned off. The ECM isn't involved since the EBCM just doesn't send a torque request message across the data link to the ECM. Hard to see how lack of a message would cause the ECM to screw up unless somebody was screwing around with the wiring and cobbing things up. I would ignore this for now.

The first thing I would do is pull the ECM and start looking at the connectors that connect to the ECM. Inspect them for dirt, corrosion, loose pins, loose sockets, etc. Make sure everything is clean and making great contact. This is a little time consuming but if you do it yourself you can do it for free. Get the diagnostics for P1516 and go through the schematics and connector end views to see where to look and what signals are involved in each connector (TAC, TB, etc).

You have to start somewhere so start with the simple easy to check things.

Bill

 

Thanks for the info. I just put a new PCM in yesterday. I checked the pins on the PCM and looked and cleaned up the ones on the wire harness the best I could. Didn't really see any corrosion, ect. Guess I will take it part again and go hole by hole. Thanks again. Guess I have a lot of details to sort throught.

 

Okay more confusing info. I cleans all connection w PCM and wiring harness. All look clean no corrosion. Cleaned some other connections by battery. No signs of dirt or corrosion. Took throttle body harness off throttle body itself. Cleaned an rust free. Started it back up ran good with no codes as long as traction control stays on. With the traction control off, I bump the throttle and it instantly goes into limp mode. Doesn't make sense because shouldn't it do it with or without the traction control button on/off? I am not moving while checking this. I am just sitting at idle with clutch in and playing with gas pedal. Any suggestion or direction to look.

 

ttt

 

Ttt

 

hmm it doesn't happen until you turn tcs off and touch the gas. Could be the throttle scaling for tcs is off in the tune and throwing the car into limp mode.

 

Turning TC off or on doesn't affect throttle scaling in the tune. There is no need to do it. The ECM doesn't know or care that TC is on or off. It responds to torque reduction requests from the EBCM and the EBCM only sends those when they are required. The EBCM makes all traction control decisions.

Bill

 

traction control off has a different throttle map than traction control on. If the map is too aggressive it will put the car into limp mode. If the problem only arises when he touches the gas with tcs off then it could be the throttle map.

 

 

Thanks so much. I think it is in the tune too. I never had this problem with the old tune. Funny how it just started after the tune. I will look into it. I am trying to get all my duck in a row so when I go back to the tune place we can try everything. I appreciate both of your help!

Dave

 

well for a follow up on this thread......They re-flashed my PCM with Gen Tech II and then re-tuned and now I have no issues at all. Hope this helps someone......Thanks for all your help

 

Good news.

 

Ran into that before myself.