Component Tests and General Diagnostics

WHEEL SPEED SENSOR OUTPUT VOLTAGE CHECK

1. Lift up the vehicle and release the parking brake.








2. Disconnect the ECU harness connector and measure from the harness side connector.

CAUTION: Set the special tool and use the check connector to inspect. Do not connect the connector (Special Tool) as marked except when recording the waveform on a driving test. In such a case, connect the connector to the ECU.





3. Rotate the wheel to be measured at approximately 1/2 - 1 rotation per second, and check the output voltage using a circuit tester or an oscilloscope.

Output voltage:

When measuring with a circuit tester: 70 mV or more

When measuring with an oscilloscope: 200 mV p-p or more

CAUTION:
1. Use the special tool (MB991 356) to check the ABS-ECU terminal voltage and resistance.

2. The ABS-ECU connector terminal arrangement for troubleshooting is different from the terminal arrangement shown on the special tool connector. So take the readings from the terminal numbers of the special tool when checking.

4. If the output voltage is lower than the above values, the reason could be as follows:
- Faulty wheel speed sensor.