Electronic Throttle Control Indicator

Electronic Throttle Control Indicator

The electronic throttle control indicator is serviced as a unit with the instrument cluster.

The ETC indicator gives an indication to the vehicle operator when the ETC system, or a circuit or component of the system is ineffective. The ETC indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the PCM over the controller area network data bus.

The ETC indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED will always be OFF when the ignition switch is in any position except ON or START. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn ON the ETC indicator for the following reasons:

• Bulb Test - Each time the ignition switch is turned to the ON position the ETC indicator is illuminated for about 3 seconds, but no longer than 15 seconds. The entire bulb test is a function of the instrument cluster.

• ETC Indicator Lamp-On Message - Each time the cluster receives an electronic ETC indicator lamp ON message from the PCM, the ETC indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the PCM message. The indicator remains illuminated solid or continues to flash for about 12 seconds or until the cluster receives a lamp OFF message from the PCM, whichever is longer. If the indicator is illuminated solid with the engine running the vehicle will usually remain drivable. If the indicator is flashing with the engine running the vehicle may require towing. A flashing indicator means the ETC system requires immediate service. The indicator will be extinguished when the ignition switch is turned to the OFF position.

• Actuator Test - Each time the cluster is put through the actuator test, the ETC indicator will be turned ON, then OFF again during the bulb test portion of the test to confirm the functionality of the LED and the cluster control circuitry. The actuator test illumination of the ETC indicator is a function of the PCM.

The PCM continually monitors the ETC system circuits and sensors to decide whether the system is in good operating condition. The PCM then sends the proper lamp ON or lamp OFF message to the electromechanical instrument cluster. If the PCM sends a lamp ON message after the bulb test, it indicates that the PCM has detected an ETC system malfunction or that the ETC system is ineffective. The PCM will store a DTC for any malfunction it detects.

A diagnostic scan tool is required for proper diagnosis of the ETC system, the PCM, the EMIC, the CAN data bus or the electronic communication related to ETC indicator operation. Refer to the appropriate diagnostic information.