Advanced Diagnostics

DTC P2108: Throttle Actuator Control Module Problem




General Description
The electronic throttle control system controls (ETCS) the throttle valve opening. The system is composed of the throttle actuator, the throttle valve, throttle position (TP) sensors A and B, the throttle actuator control module, the throttle actuator control module relay, the accelerator pedal position (APP) sensor, and the engine control module (ECM)/powertrain control module (PCM).

The APP sensor is operated via the throttle cable to determine the accelerator opening value when the driver presses the accelerator pedal. The accelerator pedal opening value is converted to a signal in the APP sensor and transmitted to the ECM/PCM to compute the target position. The target position signal is then transmitted to the throttle actuator control module.

The throttle actuator control module determines the throttle valve target position according to the signal received, and it operates the throttle actuator to move the throttle valve to the target position. The actual throttle valve position is determined by TP sensor A installed in the throttle body.

The CPU in the throttle actuator control module performs self-diagnosis for the ROM, the RAM, and the A/D converter. If internal data is found to be abnormal, a malfunction is detected and the malfunction data is transmitted to the ECM/PCM. When the ECM/PCM receives the malfunction data from the throttle actuator control module, the ECM/PCM detects a malfunction in the throttle actuator control module and stores a DTC. When the ECM/PCM monitors the serial signal between the ECM/PCM and the throttle actuator control module and these signals do not agree, the ECM/PCM detects a malfunction and a DTC is stored.




Monitor Execution, Sequence, Duration, DTC Type, OBD Status




Enable Conditions

Malfunction Threshold
One of these conditions must be met.

- Data read from the ROM is abnormal.
- Data read from the RAM is abnormal.
- The A/D converter standard voltage is out of specified value.
- The serial signals between the ECM/PCM and the throttle actuator control module do not agree.

Diagnosis Details

Conditions for illuminating the MIL
When a malfunction is detected, the MIL comes on and the DTC and the freeze frame data are stored in the ECM/PCM memory.

Conditions for clearing the MIL
The MIL will be cleared if the malfunction does not recur during three consecutive trips in which the diagnostic runs.

The MIL, the DTC, and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.