DTC P0500 : VEHICLE SPEED SENSOR (VSS) MALFUNCTION
If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system.
Anti-Lock Brake System (ABS) Vehicle Speed Sensor (VSS) detects wheel speed and sends signals to ABS ECU. The ABS ECU converts signals into a 4-pulse signal and outputs signal to instrument cluster. Instrument cluster converts signal to a more precise waveform and outputs signal to ECM. ECM determines vehicle speed based on frequency of these pulse signals. DTC is set when ECM does not detect any VSS signal while vehicle is in motion. Possible causes are:
a) Faulty vehicle speed sensor.
B) Open or short in VSS circuit.
C) Faulty instrument cluster.
D) Faulty ECM.
Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.
Diagnosis & Repair
1. Test drive vehicle and check operation of speedometer. If speedometer is not operating correctly, repair speedometer as necessary. If speedometer is operating correctly, go to next step.
2. Access ECM behind glove box. Turn ignition off. Disconnect ECM E9
connector. See Fig. 2. Using voltmeter, check for continuity between ground and terminal No. 22 (Violet/White wire) at ECM E9 harness connector. If continuity does not exist, go to next step. If continuity exists, locate and repair short to ground in Violet/White wire between ECM E9 connector and instrument cluster.
3. Turn ignition on. Measure voltage between ground and terminal No. 22 (Violet/White wire) at ECM E9 harness connector. If voltage is 9
-14 volt, go to next step. If voltage is not 9-14 volts, locate and repair open in Violet/White wire between junction connector IJ1 and ECM. Connector IJ1 is a 16-pin connector located behind glove box.
4. Check for open in Violet/White wire between junction block IJ1 and instrument cluster. Repair wiring as necessary and retest system. If wiring is okay, replace ECM and retest system.
Is P0765 still present?
Tuesday, July 12th, 2011 AT 11:48 AM