Site Update: T/C going off for no reason (found one reason)

[standby-V]

I've lived with this T/C light going off and have heard many reasons why folks here are still trying to analyze why it goes off . Back in 06 I found the exhaust module in the trunk and cut the red wire and put a switch in my console to make it go from mild to wild whenever I wanted too. Then a company made a nicer version that was controlled by one of the three buttons on the visor (Mild to Wild) I found that after many years if I had the exhaust turned on wild after I sat with the engine running at a light or in stop & go traffic, it would effect the module in some fashion and the T/C light would go on. Having left this feature work by RPM's instead of bypassing it, the light doesn't come on anymore. Just a tip that may work for you.

 

[Phrede]

View attachment 3022View attachment 3023View attachment 3024I've lived with this T/C light going off and have heard many reasons why folks here are still trying to analyze why it goes off . Back in 06 I found the exhaust module in the trunk and cut the red wire and put a switch in my console to make it go from mild to wild whenever I wanted too. Then a company made a nicer version that was controlled by one of the three buttons on the visor (Mild to Wild) I found that after many years if I had the exhaust turned on wild after I sat with the engine running at a light or in stop & go traffic, it would effect the module in some fashion and the T/C light would go on. Having left this feature work by RPM's instead of bypassing it, the light doesn't come on anymore. Just a tip that may work for you.

Anyone else have this problem?

 

[XLR-V Lover]

Nope, but if Standby found one of the possible reasons we get that message good for him. These cars acted pretty strange sometimes when they were new, God only knows how many and how often we'll get various messages now that they're beginning to age.

 

[onalaska]

View attachment 3022View attachment 3023View attachment 3024I've lived with this T/C light going off and have heard many reasons why folks here are still trying to analyze why it goes off . Back in 06 I found the exhaust module in the trunk and cut the red wire and put a switch in my console to make it go from mild to wild whenever I wanted too. Then a company made a nicer version that was controlled by one of the three buttons on the visor (Mild to Wild) I found that after many years if I had the exhaust turned on wild after I sat with the engine running at a light or in stop & go traffic, it would effect the module in some fashion and the T/C light would go on. Having left this feature work by RPM's instead of bypassing it, the light doesn't come on anymore. Just a tip that may work for you.

I have a switch in series with the brown wire coming out of the module. That is the wire that actually controls the vacuum solenoid that opens the bypass valve and have never had a problem with the T/C light. The red wire powers the exhaust module and cutting the power to it may be causing a communications error as the module probably communicates with the rest of the computers in the car and when it's power is cut it may be registering a fault.

 

[Phrede]

I have a switch in series with the brown wire coming out of the module. That is the wire that actually controls the vacuum solenoid that opens the bypass valve and have never had a problem with the T/C light. The red wire powers the exhaust module and cutting the power to it may be causing a communications error as the module probably communicates with the rest of the computers in the car and when it's power is cut it may be registering a fault.

This is a good thought.

I installed my Mild-2-Wild unit connecting in series with the RED/WHT wire (+12 volts to the module), pin 2 of C2, per the instructions. Mine does not have a red wire without the white tracer.

While this method does disconnect power from the module, I suppose it will still "open up" the exhaust when in mild mode if the factory criteria are met. I'm not sure about this nor do I know if it matters to have more back pressure at WOT and high RPMs

Onalaska, is the exhaust in "open mode" when there is no power to the solenoid? Did you simply break the circuit with a switch or did you have to supply power to the solenoid?

Also, I seem to remember reading somewhere that the vacuum valve always starts out open indicating it needs vacuum to be closed/quieter.

 

[standby-V]

Exhaust module

This sounds reasonable to me and that just might be my problem. The only time I use it now is when cruising in parking lots for the rumble in the jungle noise. Good job

 

[onalaska]

This is a good thought.

I installed my Mild-2-Wild unit connecting in series with the RED/WHT wire (+12 volts to the module), pin 2 of C2, per the instructions. Mine does not have a red wire without the white tracer.

While this method does disconnect power from the module, I suppose it will still "open up" the exhaust when in mild mode if the factory criteria are met. I'm not sure about this nor do I know if it matters to have more back pressure at WOT and high RPMs

Onalaska, is the exhaust in "open mode" when there is no power to the solenoid? Did you simply break the circuit with a switch or did you have to supply power to the solenoid?

Also, I seem to remember reading somewhere that the vacuum valve always starts out open indicating it needs vacuum to be closed/quieter.
View attachment 3051

Without power the solenoid valve leaves the exhaust butterfly valves open. I believe it is vacuum to close the exhaust. The switch just kills power to the solenoid. By the way my exhaust valves would never open regardless of engine RPM. I even purchased another GMPP exhaust control board and it made no difference so I have to open the circuit to the valve to get it to work. It is supposed to open above 3500 RPM. I even checked and there is data going to the board so I just gave up and use the switch when I want it loud.

 

[standby-V]

Right, that's what happens when you cut the red wire, I didn't give thought to the vacuum that the engine is probably loosing air and throwing the T/C on. I have mentioned this before that if your a two footed driver which comes from either NASCAR OR DRAG RACING, and your in on both at the same time it's gonna kick the T/C light on, just happened to me twice in last hour. I have to relearn to drive with one foot.

Without power the solenoid valve leaves the exhaust butterfly valves open. I believe it is vacuum to close the exhaust. The switch just kills power to the solenoid. By the way my exhaust valves would never open regardless of engine RPM. I even purchased another GMPP exhaust control board and it made no difference so I have to open the circuit to the valve to get it to work. It is supposed to open above 3500 RPM. I even checked and there is data going to the board so I just gave up and use the switch when I want it loud.

 

[standby-V]

T/C light

Latest find..........Steering wheel center sensor, whatever that is, was bad. Cant believe it took 5 years to figure this out. In the beginning on the 04 it was the gas cap that was changed out on many cars.