[35B] ANTI-SKID BRAKING SYSTEM (ABS) - - ON-VEHICLE SERVICE - ABS SENSOR OUTPUT VOLTAGE MEASUREMENT | PRINT PAGE / INDEX / PRIOR / NEXT

ON-VEHICLE SERVICE

| ABS SENSOR OUTPUT VOLTAGE MEASUREMENT
| Lift up the vehicle and release the parking brake.
| Disconnect the ABS-ECU connector B-03, and measure the output voltage at the harness side connector. Manually turn the wheel to be measured 1/2 to 1 turn/second. Measure the output voltage with a voltmeter or oscilloscope.
Terminal No.
Front left | Front right | Rear left | Rear right
16 | 9 | 27 | 11
26 | 10 | 28 | 17
| Output voltage: 42 mV or higher when measured using a multimeter 120 mVP-P or higher when measured using a oscilloscope If the output voltage is lower than that given above, the cause may be the following, so check or replace the wheel speed sensor if necessary. ABS sensor pole piece-to-ABS rotor clearance too large Faulty ABS sensor
| WAVE PATTERN INSPECTION USING AN OSCILLOSCOPE After checking the connection of the wheel speed sensor harness and the connector, take a reading of the output voltage wave patterns for each wheel speed sensor using an oscilloscope as follows. Start the engine, the transmission selector lever to D range, and then spin the wheel.
| NOTE: You can also take a reading of the wave pattern by actually driving the vehicle in this condition. The output voltage will be lower when the wheel speed is lower, and will become higher as the wheel speed becomes higher.
POINTS IN WAVEFORM MEASUREMENT
Symptom | Probable causes | Remedy
--- | --- | ---
Too small or zero waveform amplitude | Faulty ABS sensor | Replace sensor
Waveform amplitude fluctuates excessively (This is no problem if the minimum amplitude is 100 mV or more) | Axle hub eccentric or with large runout | Replace hub
Faulty ABS-ECU earth | Repair harness
Noisy or disturbed waveform | Open circuit in ABS sensor | Replace sensor
Open circuit in harness | Repair harness
Incorrectly mounted ABS sensor | Mount correctly
ABS rotor with missing or damaged teeth | Replace ABS rotor
NOTE: The ABS sensor cable moves in relation to motion of the front or rear suspension. Therefore, it is likely that it has an open circuit only when driving on rough roads but it functions normally when driving on smooth roads. It is recommended to observe sensor output voltage waveform also under special conditions, such as driving on a rough road.

[35B] ANTI-SKID BRAKING SYSTEM (ABS) - - ON-VEHICLE SERVICE - ABS SENSOR OUTPUT VOLTAGE MEASUREMENT | PRINT PAGE / INDEX / PRIOR / NEXT

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