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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> Brakes >> Anti-Lock Brakes >> Abs With EBD & BA & TRAC & VSC System - Diagnostics >> Circuit Inspection >> DTC C0200/31-C1331/36, DTC C1332/38 & C1333/39 Speed Sensor Circuit >> Inspection Procedure

Inspection Procedure

NOTE:

Start the inspection from step  1 in case of using the hand-held tester and start from step  2 in case of not using the hand-held tester.

  1. Check output value of speed sensor  .
    1. Connect the hand-held tester to the DLC3.
    2. Turn the ignition switch ON and push the hand-held tester main switch ON.
    3. Select the DATALIST mode on the hand-held tester.

    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.

    NOTE: There is tolerance of +/- 10 % in the speedometer indication.

    OK: There is almost no difference from the displayed speed value  .

    1. OK: Go to step   4  .
    2. NG: Go to next step  .

  2. Check speed sensor  .

    FRONT 

    1. Remove the front fender liner.
    2. Make sure that there is no looseness at the connector lock part and connecting part of the connector.
    3. Disconnect the speed sensor connector.

    Measure the resistance between terminals 1 and 2 of speed sensor connector.

    OK: Resistance: 0.9 - 1.8 k/Ohms at 20 °C (68 °F) 

    Fig 1: Testing Front Speed Sensor
    G01081173Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    Measure the resistance between terminals 1 and 2 of speed sensor connector and body ground.

    OK: Resistance: 1 M/Ohm or higher  .

    REAR 

    1. Make sure that there is no looseness at the connector lock part and connecting part of the connector or rear under floor.
    2. Disconnect the speed sensor connector.

    Measure the resistance between terminals 1 and 2 of speed sensor connector.

    OK: Resistance: 0.9 - 1.3 k/Ohm at 20 °C (68 °F)  .

    Fig 2: Testing Rear Speed Sensor
    G01081174Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    Measure the resistance between terminals 1 and 2 of speed sensor connector and body ground.

    OK: Resistance: 1 M/Ohm or higher  .

    1. OK: Go to next step  .
    2. NG: Replace front speed sensor or rear axle hub or rear skid control wire  .
      NOTE: Check the speed sensor signal last. See  2.
  3. Check for open and short circuit in harness and connector between each speed sensor and Skid Control ECU. See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  .
    1. OK: Go to next step  .
    2. NG: Repair or replace harness or connector  .
  4. Check front speed sensor installation  .

    Check the speed sensor installation.

    Fig 3: Identifying Possible Cause Of Speed Sensor Malfunction
    G01081175Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    Torque: 8.0 N.m (82 Kgf. cm, 71 In. Lbs)  .

    OK: The installation bolt is tightened properly and there is no clearance between the sensor and knuckle  .

    1. OK: Go to next step  .
    2. NG: Reinstall or replace front speed sensor  .
      NOTE: Check the speed sensor signal last. See  2.

  5. Check rear speed sensor and sensor rotor serrations  .

    Reference: inspection using oscilloscope 

    1. Disconnect the connector from the Skid Control ECU.
    2. Connect the oscilloscope to the each of terminals RR+ - RR- or RL+ - RL- of the ECU harness side connector.

    Drive the vehicle at about 30 km/h (19 mph), and check the signal waveform.

    Fig 4: Identifying Normal Signal Waveform
    G01081176Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    NOTE:
    • As the vehicle speed (RPM of the wheels) 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.
    1. OK: Go to next step  .
    2. NG: Replace rear axle hub  .
  6. Check front speed sensor and sensor rotor serrations  .

    Reference: inspection using oscilloscope 

    1. Disconnect the connector from the Skid Control ECU.
    2. Connect the oscilloscope to the each of terminals FR+ - FR- or FL+ - FL- of the ECU harness side connector.

    Drive the vehicle at about 30 km/h (19 mph), and check the signal waveform.

    Fig 5: Identifying Normal Signal Waveform
    G01081177Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    NOTE:
    • As the vehicle speed (RPM of the wheels) 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.
    1. OK: Check and replace Skid Control ECU  .
    2. NG: Go to next step  .
  7. Check front sensor rotor and sensor tip  .

    Remove the front drive shaft. See SIENNA .

    Check the sensor rotor serrations.

    OK: No scratches, missing teeth or foreign objects  .

    Remove the front speed sensor. See REMOVAL .

    Check the sensor tip.

    Fig 6: Inspecting Front Rotor Serrations
    G01081178Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: No scratches or foreign objects on the sensor tip  .

    NOTE:

    If foreign matter (including that on the sensor rotor side) is identified, remove it and after reassembling, check the output waveform.

    1. OK: Check and replace Skid Control ECU  .
    2. NG: Replace sensor rotor or speed sensor  .
      NOTE: Check the speed sensor signal last. See  2.
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