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Home >> Toyota >> 2007 >> Tundra Base, 4.0 U >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (1GR-FE) - System Testing, On-Vehicle Inspection, Removal, Inspection & Installation >> A/F Sensor Heater Relay >> On-Vehicle Inspection

On-Vehicle Inspection

  1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL 
    NOTE:
    • Some systems need to be initialized after the cable is reconnected (see INITIALIZATION ).
    • After the ignition switch is turned OFF, the navigation system requires approximately 90 seconds to record various types of memory and settings. As a result, after turning the ignition switch OFF, wait 90 seconds or more before disconnecting the cable from the negative (-) battery terminal.
  2. REMOVE INTEGRATION RELAY (UNIT E) 
    1. Remove the engine room relay block cover.
    2. Using a screwdriver, detach the 2 claws and disconnect the integration relay from the engine room relay block.

      HINT:

      Tape the screwdriver tip before use.

    3. Disconnect the 3 connectors.
      Fig 1: Removing Integration Relay (Unit E)
      G05149628Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. INSPECT INTEGRATION RELAY (A/F SENSOR HEATER RELAY) 
    NOTE:
    • Some relays are built into the integration relay (unit E). The integration relay cannot be disassembled. If there is a malfunction in the circuit of the integration relay, replace the integration relay.
    • The internal circuit of the integration relay is as shown in the illustration below. Inspect the integration relay using the following procedures.
      Fig 2: Integration Relay (Unit E) Inner Diagram
      G05149636Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Measure the resistance of the A/F fuse.
      1. Measure the resistance according to the value(s) in the table below.

        Standard resistance 

        A/F FUSE

        Tester Connection Condition Specified Condition
        A/F fuse Always Below 1 Ω

        If the result is not as specified, replace the A/F fuse.

    2. Measure the resistance of the A/F relay circuit.
      1. Measure the resistance according to the value(s) in the table below.

        Standard resistance 

        A/F RELAY CIRCUIT

        Tester Connection Condition Specified Condition
        1C-1 - 1A-4 When battery voltage is not applied between 1A-2 and 1A-3 10 kΩ or higher
        When battery voltage is applied between 1A-2 and 1A-3 Below 1 Ω

        If the result is not as specified, replace the integration relay.

  4. INSTALL INTEGRATION RELAY (UNIT E) 
    1. Connect the 3 connectors.
    2. Install the integration relay to the engine room relay block.
      Fig 3: Identifying Integration Relay Connector Terminals
      G05149633Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Install the engine room relay block cover.
  5. CONNECT CABLE TO NEGATIVE BATTERY TERMINAL 
    NOTE: Some systems need to be initialized after the cable is reconnected (see INITIALIZATION ).
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