Inspection Procedure
HINT:
Start the inspection from step 1 when using the hand-held tester and start from 2 when not using hand-held tester.
- Check output value of speed sensor.
PREPARATION:
- Connect the hand-held tester to the DLC3.
- Turn the ignition switch ON and push the hand-held tester main switch ON.
- Select the DATA LIST mode on the hand-held tester.
CHECK:
Check that there is no difference between the speed value output from the speed sensor displayed on the hand-held tester and the speed value displayed on the speedometer when driving the vehicle.
OK:
There is almost no difference from the displayed speed values.
HINT:
There is tolerance of +/- 10 % in the speedometer indication.
- OK: Go to step 4 .
- NG: Go To Next Step
- Check speed sensor.
Front speed sensor:
PREPARATION:
- Remove the front fender liner.
- Make sure that there is no looseness at the connector lock part and connecting part of the connector.
- Disconnect the speed sensor connector.
CHECK:
Measure the resistance between terminals 1 and 2 of the speed sensor connector.
OK:
Resistance: 0.6 to 2.5 kΩ at -40 to 120°C (-40 to 248°F)
CHECK:
Measure the resistance between terminals 1 and 2 of the speed sensor connector and the body ground.
OK:
Resistance: 10 MΩ or higher
Rear speed sensor (2WD):
PREPARATION:
- Make sure that there is no looseness at the connector lock part and connecting part of the connector.
- Disconnect the speed sensor connector at the hub bearing.
CHECK:
Measure the resistance between terminals 1 and 2 of the speed sensor connector.
OK:
Resistance: 0.8 to 1.9 kΩ at -40 to 120°C (-40 to 248°F)
CHECK:
Measure the resistance between terminals 1 and 2 of the speed sensor connector and the body ground.
OK:
Resistance: 1 MΩ or higher
Rear speed sensor (4WD):
PREPARATION:
- Make sure that there is no looseness at the connector lock part and connecting part of the connector.
- Disconnect the speed sensor connector at the hub bearing.
CHECK:
Measure the resistance between terminals 1 and 2 of the speed sensor connectors.
OK:
Resistance: 0.65 to 1.8 kΩ at -40 to 120°C (-40 to 248°F)
CHECK:
Measure the resistance between terminals 1 and 2 of the speed sensor connector and the body ground.
OK:
Resistance: 1 MΩ or higher
Rear speed sensor sub-wire harness (2WD):
PREPARATION:
- Remove the seat cushion and seat back.
- Make sure that there is no looseness at the connector lock part and connecting part of the connector.
- Disconnect the speed sensor connector inside the vehicle.
CHECK:
- Measure the resistance between terminal 1 of connector 1 and terminal 2 of connector 2.
- Measure the resistance between terminal 2 of connector 1 and terminal 1 of connector 2.
OK:
Resistance: Below 1 Ω
CHECK:
Measure the resistance between terminals 1 and 2 of the speed sensor connector 1 and the body ground.
OK:
Resistance: 10 MΩ or higher
- NG: Replace speed sensor or sub-wire harness. NOTE: Finally, check the speed sensor signal (see PRE-CHECK ).
- OK: Go To Next Step.
- Check for open and short circuit in harness and connector between each speed sensor and skid control ECU with actuator (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE
).
- NG: Repair or replace harness and connector.
- OK: Go To Next Step.
- Check sensor installation.
CHECK:
Check the speed sensor installation.
OK:
FRONT (2WD, 4WD), Rear (4WD):
The installation bolt is tightened properly and there is no clearance between the sensor and steering knuckle or rear axle carrier.
Torque: 8.0 Nm (8.2 kgf.cm, 71 in.lbf).
Rear (2WD):
There is no clearance between the sensor and rear axle carrier.
- NG: Replace speed sensor. NOTE: Finally, check the speed sensor signal (see PRE-CHECK ).
- OK: Go To Next Step.
- NG: Replace speed sensor.
- Check speed sensor and sensor rotor serrations.
(REFERENCE) INSPECTION USING OSCILLOSCOPE
PREPARATION:
Connect an oscilloscope to terminals FR+ - FR-, FL+ - FL-, RR+ - RR- and RL+ - RL- of the ABS actuator with ECU.
CHECK
Drive the vehicle at about 20 km/h (12 mph), and check the signal waveform.
OK:
A waveform as shown in a figure should be output.
HINT:
- As the vehicle speed (wheel revolution speed) increases, a cycle of the waveform becomes shorter and the fluctuation in the output voltage becomes greater.
- When noise is identified in the waveform on the oscilloscope, error signals are generated due to the speed sensor rotor's scratches, looseness or foreign matter deposited on it.
- OK: Replace brake actuator assembly. NOTE: When replacing the brake actuator assembly, perform the zero point calibration (see PRE-CHECK ).
- NG: Go To Next Step.
- Check sensor rotor and sensor tip.
Front:
PREPARATION:
Remove the front drive shaft (see REMOVAL ).
CHECK:
Check sensor rotor serrations.
OK:
No scratches, missing teeth or foreign objects.
PREPARATION:
Remove the front speed sensor (see REMOVAL ).
CHECK:
Check the sensor tip.
OK:
No scratches or foreign objects on the sensor tip.
NOTE: Finally, check the speed sensor signal (see PRE-CHECK ).Rear (2WD):
PREPARATION:
Remove the axle hub and disconnect the rear speed sensor (see REMOVAL ).
CHECK:
Check the sensor rotor serrations.
OK:
No scratches or missing teeth or no foreign objects.
CHECK:
Check the sensor tip.
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OK:
No scratches or no foreign objects on the sensor tip.
Rear (4WD):
PREPARATION:
Remove the rear drive shaft (see REMOVAL ).
CHECK:
Check the sensor rotor serrations.
OK:
No scratches or missing teeth or no foreign objects.
HINT:
If foreign objects are stuck to the rotor, remove them.
PREPARATION:
Remove the rear drive shaft (see REMOVAL ).
CHECK:
Check the sensor tip.
OK:
No scratches or no foreign objects on the sensor tip.
HINT:
If foreign objects are stuck to the sensor tip, remove them before reuse. Check the rotor for the presence of foreign objects and remove them if they are stuck.
- NG: Replace speed sensor or rear axle hub assembly. NOTE: Finally, check the speed sensor signal (see PRE-CHECK ).
HINT:
Remove any foreign matters if identified.
Check the output waveform again after reassembling.
- OK: Replace brake actuator assembly.
NOTE: When replacing the brake actuator assembly, perform the zero point calibration (see PRE-CHECK ). - NG: Replace speed sensor or rear axle hub assembly.