Code U0107

[BR3W CITY]

My new engine runs great but when I rev it, it will throw a U0107 code and lose communication with the TAC module. It only gets 1 press of the gas, then loses communication. Anyone dealt with something like this? The TAC and gas pedal were bought as a pair, so there shouldn't be incompatability issues.

[68GMCCustom]

your sig says "Big Cam LQ4". What are the specs?

[clinebarger]

Code Setting Conditions:

Key in the Crank or Run position; system voltage over 5.23v, valid communication between the TAC module and the PCM established, and the PCM detected Invalid or missing serial data messages for more than 0.83 second. The TAC module and the PCM communicate via a dedicated serial data circuit. This serial data circuit is separate from other serial data circuits on the vehicle. Accurate transmitting and receiving of serial data requires good circuit integrity, and also adequate system voltage. This code monitors the accuracy of the serial data transmitted between the TAC module and PCM. If the PCM detects a loss of data or invalid data, DTC U0107 sets.

Potential Causes:
Malfunctioning TAC Module
Improper TAC Module Power
Improper TAC Ground
Damaged UART Wiring

Test voltage backprobed at the TAC module C1 Blue connector terminal 7 Pink wire ignition power (key on and cranking).

Test terminal 15 Black wire for a good ground. If you have a poor ground.....Inspect/clean/secure ground G104 at rear end of left cylinder head. And G103 at top rear of engine next to inboard edge of the right cylinder head.

Inspect the serial data wires pin 12 Orange/Black and pin 13 Dark Blue/White between the TAC module connector C1 and PCM connector C1. These are dedicated Universal Asynchronous Receive Transmit (UART) serial data lines.

[usmcchevy]

Searched a bit, all I can find is check your TAC ground+power and all wires between TAC and computer. good luck

EDIT: I'm way slower and not nearly as good as clinebarger

[BR3W CITY]

Thanks guys, I read a little more into it and made some progress. It turns out this code is thrown when there is a mis-match of parts in the TAC system. SO it looks like it breaks down something like this:

TAC, pedal, ECM, and Throttle body must all be within a certain year/pn# range to work together. I have a 2004 ECM, so my TAC and pedal need to match the 03-05 style...the metal pedal kind. I purchased an 06-07 (plastic pedal) setup, which will only work with 06+ computers. I don't know WHY, but GM decided that both TAC modules should look exactly the same, and have the same plug ins.

Now it goes a bit further. Because I can hear my throttle blade switch back and forth, I know it registers the TAC and pedal, BUT it throws the code after 1 rev. In 06 the design changed from what I understand, and incorporated 2 potentiometers (sp?) instead of 1. One reads 0-10v starting open, the other reads 10-0v starting closed, they act as a failsafe to each other. The extra signal shows a random voltage change to the ECM, which on an 03-05 causes an error and trips the code.

Hopefully getting the correct 03-05 tac and pedal should correct the issues and have me on the road.