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Home >> Toyota >> 2005 >> RAV4 Base, AWD, Standard >> Repair and Diagnosis >> Brakes >> Anti-Lock Brakes >> Brakes - Abs With EBD & BA & TRAC & VSC (Diagnostics) >> Circuit Inspection >> Diagnostic Trouble Codes Always ON* Malfunction in Skid Control ECU >> Inspection Procedure

Inspection Procedure

  1. Is DTC output? 

    Check for DTC (see PRE-CHECK ).

    1. YES: Repair circuit indicated by output code. 
    2. NO: Go To Next Step 
  2. Check that skid control ECU connector are securely connected to skid control ECU. 
    1. NG: Connect connector to skid control ECU. 
    2. OK: Go To Next Step 
  3. Measure voltage between terminals IG1 and GND1 of brake actuator connector. 

    PREPARATION: 

    Disconnect the brake actuator connector.

    CHECK: 

    1. Turn the ignition switch ON.
    2. Measure the voltage between terminal IG1 and GND1 of the skid control ECU harness side connector.

    OK: 

    Voltage: 10 to 14 V 

    Fig 1: Identifying IG1 And GND1 Terminals Of Skid Control ECU Harness Side Connector
    G02642431Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: Check for open and short circuit in harness and connector between ECU-IG fuse and skid control ECU (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ). 
    2. OK: Go To Next Step 
  4. Measure resistance between terminal GND1 of skid control ECU connector and body ground. 

    PREPARATION: 

    Disconnect the brake actuator connector.

    CHECK: 

    Measure the resistance between terminal GND1 of the skid control ECU harness side connector and body ground.

    OK: 

    Resistance: Below 1Ω 

    Fig 2: Identifying GND1 Terminal Of Skid Control ECU Harness Side Connector
    G02642432Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: Repair or replace harness and connector. 
    2. OK: Go To Next Step 
  5. Measure battery positive voltage. 

    CHECK: 

    Check the battery positive voltage.

    OK: 

    Voltage: 10 to 14 V 

    1. NG: Check and repair charging system (See  CHARGING SYSTEM  ). 
    2. OK: Go To Next Step 
  6. Check operation of ABS warning light. 

    PREPARATION: 

    1. Turn the ignition switch OFF.
    2. Disconnect the connector from the brake actuator.
    3. Ground terminal WA of the skid control ECU.
    4. Turn the ignition switch ON.

    CHECK: 

    Check that the ABS warning light turns off.

    1. NG: Check and repair for ABS warning light circuit (See  CIRCUIT  ). 
    2. OK: Go To Next Step 
  7. Check ABS warning light 

    PREPARATION: 

    1. Reconnect the connector to the brake actuator.

    CHECK: 

    Check that the ABS warning light turns off.

    1. NG: Replace brake actuator assembly. 
      NOTE: When replacing the brake actuator assembly, perform the zero point calibration (see PRE-CHECK ).
    2. OK: END 


  1. Is DTC output for VSC? 

    Check for DTC (see PRE-CHECK ).

    1. YES: Repair circuit indicated by output code. 
    2. NO: Go To Next Step 
  2. Check that skid control ECU connector are securely connected to skid control ECU. 
    1. NG: Connect connector to skid control ECU. 
    2. OK: Go To Next Step 
  3. Measure voltage between terminals IG1 and GND1 of brake actuator connector. 

    PREPARATION: 

    Disconnect the brake actuator connector.

    CHECK: 

    1. Turn the ignition switch ON.
    2. Measure the voltage between terminals IG1 and GND1 of the skid control ECU harness side connector.

    OK: 

    Voltage: 10 to 14 V 

    Fig 1: Identifying IG1 And GND1 Terminals Of Skid Control ECU Harness Side Connector
    G02642435Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: Check for open and short circuit in harness and connector between ECU-IG fuse and skid control ECU (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ). 
    2. OK: Go To Next Step 
  4. Measure resistance between terminal GND1 of skid control ECU connector and body ground. 

    PREPARATION: 

    Disconnect the brake actuator connector.

    CHECK: 

    Measure the resistance between terminal GND1 of the skid control ECU harness side connector and body ground.

    OK: 

    Resistance: Below 1 Ω 

    Fig 2: Identifying GND1 Terminal Of Skid Control ECU Harness Side Connector
    G02642436Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: Repair or replace harness and connector. 
    2. OK: Go To Next Step 
  5. Measure battery positive voltage. 

    CHECK: 

    Check the battery positive voltage.

    OK: 

    Voltage: 10 to 14 V 

    1. NG: Check and repair charging system (see  CHARGING SYSTEM  ). 
    2. OK: Go To Next Step 
  6. Check TC terminal circuit (see  CIRCUIT INSPECTION  ). 
    1. NG: Repair or replace harness and connector. 
    2. OK: Go To Next Step 
  7. Check operation of VSC warning light. 

    PREPARATION: 

    1. Turn the ignition switch OFF.
    2. Disconnect the connector from the brake actuator.
    3. Turn the ignition switch ON.

    CHECK: 

    Check that the VSC warning light turns off.

    OK: 

    The VSC warning light turns off for 2 seconds after turning the ignition switch ON.

    1. OK: Replace brake actuator assembly. 
      NOTE: When replacing the brake actuator assembly, perform the zero point calibration (see PRE-CHECK ).
    2. NG: Check and repair for VSC warning light circuit (See  CIRCUIT  ). 
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