U0107 Lost Communication With Throttle Actuator Control (TAC) Module

U0107 Lost Communication With Throttle Actuator Control (TAC) Module

OBD-II DTC Datasheet

Lost Communication With Throttle Actuator Control (TAC) Module

What does this mean?

This is a generic communications DTC that applies to most makes and models of vehicles, including but not limited to Dodge, Ram, Chevrolet, Ford, GMC, and VW. This code means the Throttle Actuator Control (TAC) module and other control modules on the vehicle are not communicating with each other.

The circuitry most commonly used for communication is known as Controller Area Bus communication, or simply the CAN bus. Without this CAN bus, control modules cannot communicate and your scan tool may not receive information from the vehicle, depending on which circuit is involved.

TACM is also known as Electronic Throttle Control Module (ETC). These modules control engine speed based on information received from the powertrain control module (PCM). The main component of the TAC / ETC system is the throttle body, which is located between the intake manifold and the air filter. It will usually have one or more TAC / ETC motors to move the throttle inside and one or more Throttle Position (TPS) sensors so that the PCM always knows where the throttle is. If no information is received, the engine will only idle, typically around 1000 rpm.

Troubleshooting steps may vary depending on the manufacturer, the type of communication system, the number of wires, and the colors of the wires in the communication system.

symptoms

Symptoms of a U0107 engine code may include:

• Malfunction Indicator Light (MIL) is on
• Electronic throttle control light is on or flashing
• No throttle response - engine will only idle

reasons

Usually the reason for installing this code is:

• Open in CAN + bus circuit
• CAN bus break - electrical circuit
• Short circuit to power in any CAN bus circuit
• Short to ground in any CAN bus circuit
• Rarely - the control module is faulty

Diagnostic and repair procedures

A good starting point is always to check the Technical Service Bulletins (TSB) for your particular vehicle. Your problem may be a known issue with a known manufacturer-released fix and could save you time and money while troubleshooting.

First, look for other DTCs. If any of these are bus communication or battery / ignition related, diagnose them first. Misdiagnosis is known to occur if you diagnose the U0107 code before any of the major codes are thoroughly diagnosed and rejected.

If your scan tool can access the trouble codes and the only code you are getting from other modules is U0107, try communicating with the TAC module. If you can access the codes from the TAC module, then the U0107 code is either intermittent or a memory code. If you cannot communicate with the GPCM, then the U0107 code that the other modules are setting is active and the problem already exists.

The most common fault is loss of power or grounding.

Check all fuses supplying the TAC module on this vehicle. Check all ground connections of the TAC module. Locate ground anchorage points on the vehicle and make sure these connections are clean and secure. If necessary, remove them, take a small wire bristle brush and baking soda / water solution and clean each one, both the connector and the place where it connects.

If any repairs have been made, clear the DTCs from all modules that set the code in memory and see if U0107 returns or you can contact the TAC module. If no code is returned or communication with the TAC module is restored, the problem is most likely a fuse / connection issue.

If the code returns, look for the CAN bus connections on your specific vehicle, especially the TAC module connector. Disconnect the negative battery cable before disconnecting the connector on the TAC module. Once detected, visually inspect the connectors and wiring. Look for scratches, scuffs, exposed wires, burn marks, or molten plastic. Disconnect the connectors and carefully inspect the terminals (metal parts) inside the connectors. See if they look burnt or have a green tint indicating corrosion. If you need to clean the terminals, use an electrical contact cleaner and a plastic bristle brush. Allow to dry and apply dielectric silicone grease where the terminals touch.

Before connecting the connectors back to the TAC module, perform these few voltage checks. You will need access to a digital volt ohm meter (DVOM). Make sure you have power and ground at the TAC module. Access the wiring diagram and determine where the main power and ground sources enter the TAC module. Reconnect the battery before continuing, with the TAC module still disconnected. Connect the red lead from your volt meter to each B+ (battery voltage) source entering the TAC module connector, and the black lead from your volt meter to a good ground (if unsure, the negative battery terminal always works). You should see a battery voltage reading. Make sure you have a good ground. Connect the red lead from your volt meter to the battery positive (B+) and the black lead to each ground circuit. Once again, you should see battery voltage with each connection. If not, troubleshoot the power or ground circuit.

Next, check the two communication circuits. Find the CAN C+ (or HSCAN+) circuit and the CAN C- (or HSCAN – circuit). With the black lead of the voltmeter connected to a good ground, connect the red lead to CAN C+. With the key on and the engine off, you should see about 2.6 volts with slight fluctuations. Then connect the red lead of the voltmeter to the CAN C- circuit. You should see about 2.4 volts with slight fluctuations.

If your vehicle manufacturer does not use the CAN bus for communication between the PCM and TAC, you need to determine the appropriate voltages for this communication circuit.

If all tests pass and communication is still not possible, or you have failed to clear the U0107 trouble code, the only thing to do is to seek help from a trained automotive diagnostician, as this would indicate a faulty TAC module. Some TAC modules must be programmed or calibrated to the vehicle in order to be installed correctly. Each has its own re-learn program that must be completed after installation in the vehicle.

Related DTC discussions

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