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Anti-Lock Brake System - Diagnosis: Pre-Check

  1. Diagnosis system. 
    1. Check the warning lights and buzzer.
      1. Release parking brake pedal.
      2. When the ignition switch is turned ON, check that the ABS and BRAKE warning lights goes on for 3 seconds.
      3. When depressing the brake pedal repeatedly it may turn on the warning lights and buzzer.
      NOTE: If the indicator check result is not normal, proceed to troubleshooting for the ABS and BRAKE warning lights circuit (See ABS WARNING LIGHT CIRCUIT  , BRAKE WARNING LIGHT CIRCUIT ).
      Fig 1: Identifying ABS & BRAKE Warning Lights
      G03149568Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. In case of not using LEXUS hand-held tester: Check the DTC.
      1. Disconnect the short pin from DLC1.
        Fig 2: Disconnecting Short Pin From DLC1
        G03149569Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        Fig 3: Identifying Terminals Tc & E1 Of DLC1
        G03149570Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Using (SST 09843-18020), connect terminals Tc and E1 of DLC1.
      3. Turn the ignition switch ON.
      4. Read the DTC from the ABS warning light on the combination meter.
        NOTE:
      5. Codes are explained in the code table. See DIAGNOSTIC TROUBLE CODE CHART  .
      6. After completing the check, disconnect terminals Tc and E1 of DLC1 and turn off the display. If 2 or more malfunctions are indicated at the same time the lowest numbered DTC will be displayed 1st.
      Fig 4: Identifying Blinking Patterns For Normal Code, Code 11 & Code 21
      G03149571Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. In case of using LEXUS hand-held tester: Check the DTC.
      1. Hook up the LEXUS hand-held tester to the DLC3.
      2. Read the DTC by following the prompts on the tester screen.
      NOTE: Please refer to the LEXUS hand-held tester operator's manual for further details.
      Fig 5: Connecting Lexus Hand-Held Tester To DLC3
      G03149572Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. In case of not using LEXUS hand-held tester: Clear the DTC.
      1. Using (SST 09843-18020), connect terminals Tc and E1 of DLC1 and remove the short pin from DLC1.
      2. Turn the ignition switch ON.
      3. Clear the DTC stored in ECU by depressing the brake pedal 8 or more times within 5 seconds.
        Fig 6: Depressing Brake Pedal To Clear DTC
        G03149573Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Check that the warning light shows the normal code.
      5. Remove the (SST 09843-18020) from the terminals of DLC1.
      6. Connect the short pin to DLC1.
      NOTE: Disconnecting the battery cable during repairs will not erase the DTC in the ECU.
      Fig 7: Connecting Short Pin To DLC1
      G03149574Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. In case of using LEXUS hand-held tester: Clear the DTC.
      1. Hook up the LEXUS hand-held tester to the DLC3.
      2. Turn the ignition switch ON.
      3. Operate the LEXUS hand-held tester to erase the codes. (See LEXUS hand-held tester operator's manual.)
        Fig 8: Connecting Lexus Hand-Held Tester To DLC3
        G03149575Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    6. (Reference): Using LEXUS break-out-box and LEXUS hand-held tester, measure the ECU terminal values.
      1. Turn the ignition switch OFF.
      2. Hook up the LEXUS break-out-box and LEXUS hand-held tester to the vehicle.
      3. Turn the ignition switch ON.
      4. Read the ECU input/output values by following the prompts on the tester screen.
      NOTE:
      • LEXUS hand-held tester has a "Snapshot" function. This records the measured values and is effective in the diagnosis of intermittent problems.
      • Please refer to the LEXUS hand-held tester/LEXUS break-out-box operator's manual for further details.
        Fig 9: Connecting Lexus Break-Out-Box & Lexus Hand-Held Tester
        G03149576Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Sensor signal check (test mode). 
    NOTE: If the ignition switch is turned from ON to ACC or LOCK during test mode, DTC will be erased.
    1. In case of not using LEXUS hand-held tester: Check the sensor signal.
      1. Turn the ignition switch OFF.
      2. Using SST 09843-18020, connect terminals Ts and E1 of DLC1.
      3. Start the engine.
        Fig 10: Identifying Terminals Ts & E1 Of DLC1
        G03149577Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Check that the ABS warning light blinks.
        NOTE: If the ABS warning light does not blink, inspect the ABS warning light circuit and Ts circuit (See ABS WARNING LIGHT CIRCUIT  , TS TERMINAL CIRCUIT  ).
        Fig 11: Identifying ABS Warning Light Blinking Pattern
        G03149578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      5. Keep the vehicle in the stationary condition on the flat place for 1 sec. or more.
      6. Leaving the vehicle in the stationary condition and the brake pedal in free condition for 1 sec. or more, continue to depress the brake pedal with 98 N (10 kgf, 22 lbf) of force or more for 1 sec. or more.
      7. Leaving the vehicle in the stationary condition, depress the brake pedal with 980 N (100 kgf, 221 lbf) of force or more quickly.
        NOTE: At this time, the ABS warning light comes on for 3 sec.
      8. Drive vehicle straight forward. When driving the vehicle with the speed faster than 45 km/h (28 mph) for several seconds, check that the ABS warning light comes off.
        NOTE: There is a case that the sensor check is not completed if the vehicle has its rear wheels spun or its steering wheel steered during this check.
      9. Stop the vehicle.
      10. Using (SST 09843-18020), connect terminals Tc and E1 of DLC1.
      11. Read the number of blinks of the ABS warning light.
        NOTE:
        • See the SENSOR SIGNAL CHECK DIAGNOSTIC CODES  table.
        • If every sensor is normal, a normal code is output (A cycle of 0.25 sec. ON and 0.25 sec. OFF is repeated).
        • If 2 or more malfunctions are indicated at the same time, the lowest numbered code will be displayed 1st.
      12. After doing the check, disconnect terminals of DLC1 and turn the ignition switch OFF.
        Fig 12: Identifying Malfunction Codes 72 & 76
        G03149579Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. In case of using LEXUS hand-held tester: Check the sensor signal.
      1. Hook up the LEXUS hand-held tester to the DLC3.
      2. Do step  3 to  9.
      3. Read the DTC by following the prompts on the tester screen.
      NOTE: Please refer to the LEXUS hand-held tester operator's manual for further details.
      Fig 13: Connecting Lexus Hand-Held Tester To DLC3
      G03149580Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the DTC of the sensor function.
      SENSOR SIGNAL CHECK DIAGNOSTIC CODES

      Code No. Diagnosis Trouble Area
      C1271/71 Low output voltage of right front speed sensor
      • Right front speed sensor
      • Sensor installation
      • Sensor rotor
      C1272/72 Low output voltage of left front speed sensor
      • Left front speed sensor
      • Sensor installation
      • Sensor rotor
      C1273/73 Low output voltage of right rear speed sensor
      • Right rear speed sensor
      • Sensor installation
      • Sensor rotor
      C1274/74 Low output voltage of left rear speed sensor
      • Left rear speed sensor
      • Sensor installation
      • Sensor rotor
      C1275/75 Abnormal change in output voltage of right front speed sensor Right front speed sensor rotor
      C1276/76 Abnormal change in output voltage of left front speed sensor Left front speed sensor rotor
      C1277/77 Abnormal change in output voltage of right rear speed sensor Right rear speed sensor rotor
      C1278/78 Abnormal change in output voltage of left rear speed sensor Left rear speed sensor rotor
      C1279/79 Deceleration sensor is faulty
      • Deceleration sensor
      • Sensor installation
      C1281/81 Master cylinder pressure sensor output signal is faulty Master cylinder pressure sensor
  3. Deceleration sensor operation diagnosis system. 
    CAUTION: While checking the deceleration sensor operating diagnosis system, ABS does not work and brake system works as a conventional brake system.
  4. Deceleration sensor check. 
    1. Connect 3 dry batteries of 1.5 V in series.
    2. Connect VGS terminal to the batteries' positive (+) terminal, and GGND terminal to the batteries' negative (-) terminal, apply about 4.5 V between VGS and GGND terminals.
      NOTE: Do not apply voltage of 6 V or more to terminals VGS and GGND.
    3. Check the output voltage of GL1 and GL2 terminals.
      DECELERATION SENSOR OUTPUT VOLTAGE SPECIFICATIONS

      Symbols Condition Standard Value
      GL1 Horizontal About 2.3 V
      GL1 Lean forward 0.4 V - about 2.3 V
      GL1 Lean rearward About 2.3 V - 4.1 V
      GL2 Horizontal About 2.3 V
      GL2 Lean forward About 2.3 V - 4.1 v
      GL2 Lean rearward 0.4 V - about 2.3 V
      NOTE:
      • If the sensor is tilted too much it may show the wrong value.
      • If dropped, the sensor should be replaced with a new one.
      • The sensor removed from the vehicle should not be placed upside down.
    Fig 14: Testing Deceleration Sensor
    G03149581Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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