P2107, P2108 Throttle actuator control module processor, performance failure

Land Rover OBD-II Trouble Codes -------------------------------------------------The diagnostic trouble codes (DTCs) P2107 and P2108 both relate to issues with the Throttle Actuator Control (TAC) module. These codes indicate a problem with the performance of the TAC module processor. Here's a breakdown of each code:

Electronic Throttle Processor Error,

TAC Module Performance Fault,

PCM Internal Throttle Logic,

Drive-By-Wire System Shutdown,

Actuator Control Feedback Error,

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Diagnostic Overview

• The System: These codes relate to the Throttle Actuator Control (TAC) system. In many modern vehicles, the TAC logic is a dedicated "micro-processor" inside the main Engine Control Module (PCM/ECM) that handles the high-speed movements of the throttle blade.

• P2107 (Processor Fault): This is an internal self-test failure. The PCM has detected that its own internal processor responsible for throttle control is not calculating data correctly.

• P2108 (Performance Fault): The PCM sees that the throttle motor is not responding to commands as quickly or as accurately as the programmed software expects.

Common Failure Points

1. Low Battery Voltage: This is the #1 "ghost" cause. If the battery is weak or the alternator is failing, the sudden high-current draw required to move the throttle motor can cause the PCM processor to "glitch" and throw a P2107.

2. Throttle Body Obstruction: Heavy carbon buildup or a physical object can jam the butterfly valve. If the motor tries to move the valve and hits resistance, it triggers the P2108 performance code.

3. Internal PCM Damage: Since P2107 specifically mentions the "processor," it can sometimes indicate that the PCM itself has suffered an internal hardware failure, often due to a short circuit in the wiring harness.

4. Wiring Harness Interference: High-voltage "noise" from failing spark plug wires or a bad alternator diode can interfere with the sensitive data signals between the pedal and the PCM.

Troubleshooting Steps

• Hard Reset: Disconnect the negative battery terminal for 30 minutes. This can sometimes clear a "logic freeze" in the PCM processor.

• Inspect the Connector: Unplug the throttle body and look for Terminal Fretting. Tiny vibrations can cause the metal pins to wear down, leading to intermittent data loss.

• The "Snap" Test: With the intake boot removed and the engine off, gently push the throttle blade with your finger. It should move smoothly and "snap" back to a slightly open position via spring tension. If it feels "crunchy" or sticks, the unit is bad.

• Check Grounds: Ensure the main engine-to-chassis ground strap is clean and tight. Poor grounding is a major cause of processor communication errors.

Would you like me to find the specific "Throttle Body Relearn" steps for your vehicle, which is often required after fixing these codes?

How to Diagnose P2107 and P2108 Throttle Codes

This video explains how to differentiate between a mechanical throttle body failure and a software/electronic issue within the PCM's actuator control module.

1. **P2107 - Throttle Actuator Control Module Processor:**

   - This code suggests that there is a performance failure in the Throttle Actuator Control (TAC) module processor.

2. **P2108 - Throttle Actuator Control Module Performance:**

   - P2108 points to a more general performance issue with the TAC module.

### Possible Causes:

1. **Faulty Throttle Actuator Control Module:** Issues with the TAC module, which controls the operation of the throttle actuator.

2. **Wiring Issues:** Problems with the wiring or connectors associated with the TAC module.

3. **Electronic Control Module (ECM) Issues:** Problems with the Engine Control Module (ECM) that communicates with the TAC module.

4. **Software or Programming Issues:** Errors in the software or programming of the TAC module.

### Diagnostic Steps:

1. **Inspect Throttle Actuator Control Module:** Check the TAC module for signs of damage or wear. If it appears faulty, consider replacement.

2. **Check Wiring and Connectors:** Inspect the wiring and connectors associated with the TAC module. Look for any signs of damage, corrosion, or loose connections.

3. **Verify ECM Operation:** Test the ECM for proper operation and communication with the TAC module.

4. **Check for Software Updates:** In some cases, updating the software or programming of the TAC module may resolve performance issues.

5. **Perform Continuity Tests:** Check for continuity in the wiring from the TAC module to the ECM.

6. **Clear Codes:** After addressing any identified issues, clear the trouble codes and monitor the system for recurrence.

7. **Consider Professional Assistance:** If you are unsure about diagnosing or addressing these issues yourself, or if the faults persist, it's advisable to consult with a qualified mechanic or technician.

Addressing the root cause of the TAC module performance issues is essential for proper engine performance and throttle response. If in doubt or if the faults persist, seeking professional assistance is recommended for a thorough diagnosis and effective repair.