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Inspection Procedure

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  1. INSPECT FUSE (A/C, HTR SUB1, HTR SUB2) 
    1. Remove the A/C fuse from the main body ECU.
    2. Remove the HTR SUB1 and HTR SUB2 fuses from the engine room relay block.
    3. Measure the resistance.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Item Specified Condition
      A/C fuse Below 1 Ω
      HTR SUB 1 fuse Below 1 Ω
      HTR SUB 2 fuse Below 1 Ω
    4. Reinstall the A/C fuse.
    5. Reinstall the HTR SUB1 and HTR SUB2 fuses.

    NG: REPLACE FUSE 

    OK: GO TO NEXT STEP 

  2. INSPECT NO. 3 HEATER CONTROL KNOB 
    1. Remove the No. 3 heater control knob.
    2. Measure the resistance.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      3 (IG+) - 6 (B) Max hot position Below 1 Ω
      3 (IG+) - 6 (B) Other than max hot position 10 kΩ or higher
    3. Reinstall the No. 3 heater control knob.
      4. Fig 1: Identifying No. 3 Heater Control Knob
      G04829551Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE NO. 3 HEATER CONTROL KNOB 

    OK: GO TO NEXT STEP 

  3. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - AIR CONDITIONING AMPLIFIER) 
    1. Disconnect the E6 No. 3 heater control knob connector.
    2. Measure the voltage.

      Standard voltage 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      E6-3 (IG+) - Body ground Ignition switch ON 11 to 14 V
    3. Reconnect the No. 3 heater control knob connector.
      4. Fig 2: Identifying No. 3 Heater Control Knob Connector Terminals
      G04829552Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  4. CHECK HARNESS AND CONNECTOR (No. 3 HEATER CONTROL KNOB - AIR CONDITIONING AMPLIFIER) 
    1. Disconnect the E6 No. 3 heater control knob connector.
    2. Disconnect the E9 air conditioning amplifier connector.
    3. Measure the resistance.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Specified Condition
      E6-6 (B) - E9-14 (HEAT) Below 1 Ω
    4. Reconnect the No. 3 heater control knob connector.
    5. Reconnect the air conditioning amplifier connector.
      6. Fig 3: Identifying E6 No. 3 Heater Control Knob Connector Terminals
      G04829553Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  5. INSPECT AIR CONDITIONING AMPLIFIER 
    1. Remove the air conditioning amplifier with its connectors still connected.
    2. Turn the ignition switch ON.
    3. When the PTC heater operating conditions are met (engine at idling speed or faster, ambient temperature is 10°C (50°F) or less, engine coolant temperature is 65°C (149°F) or less, and No. 3 heater control knob setting is MAX HOT), turn the blower switch to the Lo setting.
    4. Wait 30 seconds.
    5. Measure the voltage.

      Standard voltage 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Specified Condition
      E9-9 (PTC1) - Body ground 11 to 14 V
      E9-10 (PTC2) - Body ground 11 to 14 V
      E9-12 (PTC3) - Body ground 11 to 14 V
    6. Reinstall the air conditioning amplifier.
      Fig 4: Identifying Air Conditioning Amplifier Connector Terminals
      G04829554Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE  AIR CONDITIONING AMPLIFIER  

    OK: GO TO NEXT STEP 

  6. INSPECT PTC HEATER RELAY (HTR SUB1, HTR SUB2, HTR SUB3) 
    1. Remove the HTR SUB1 relay from the engine room relay block.
    2. Remove the HTR SUB2 and HTR SUB3 relays from the engine room sub relay block.
    3. Measure the resistance.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Specified Condition
      3-5 10 kΩ or higher
      3-5 Below 1 Ω (when battery voltage is applied to terminals 1 and 2)
      Fig 5: Inspecting PTC Heater Relay (HTR SUB1, HTR SUB2, HTR SUB3)
      G04829555Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Reinstall the HTR SUB1 relay.
    5. Reinstall the HTR SUB2 and HTR SUB3 relays.

    NG: REPLACE PTC HEATER RELAY 

    OK: GO TO NEXT STEP 

  7. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - PTC HEATER RELAY) 
    1. Remove the HTR SUB1 relay from the engine room R/B.
    2. Remove the HTR SUB2 and HTR SUB3 relays from the engine room R/B No. 2.
    3. Turn the ignition switch ON.
    4. When the PTC heater operating conditions are met (engine at idling speed or faster, ambient temperature is 10°C (50°F) or less, engine coolant temperature is 65°C (149°F) or less, and No. 3 heater control knob setting is MAX HOT), turn the blower switch to the Lo setting.
    5. Wait 30 seconds.
    6. Measure the voltage.

      Standard voltage. 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Specified Condition
      HTR SUB1-2 - Body ground 11 to 14V
      HTR SUB2-2 - Body ground 11 to 14V
      HTR SUB3-2 - Body ground 11 to 14V
    7. Reinstall the HTR SUB1 relay.
    8. Reinstall the HTR SUB2 and HTR SUB3 relays.
      9. Fig 6: Identifying HTR SUB2 And HTR SUB3 Relays
      G04829556Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  8. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BODY GROUND) 
    1. Remove the HTR SUB1 relay from the engine room R/B.
    2. Remove the HTR SUB2 and HTR SUB3 relays from the engine room R/B No. 2.
    3. Measure the resistance.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Specified Condition
      HTR SUB1-1 - Body ground Below 1 Ω
      HTR SUB2-1 - Body ground Below 1 Ω
      HTR SUB3-1 - Body ground Below 1 Ω
    4. Reinstall the HTR SUB1 relay.
    5. Reinstall the HTR SUB2 and HTR SUB3 relays.
      6. Fig 7: Identifying HTR SUB2 And HTR SUB3 Relays
      G04829556Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  9. INSPECT PTC HEATER ASSEMBLY 
    1. Disconnect the A17 PTC heater assembly connector.
    2. Measure the resistance.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Specified Condition
      1-2 Below 1 Ω
      1-3 Below 1 Ω
      2-3 Below 1 Ω
    3. Reconnect the PTC heater assembly connector.
      4. Fig 8: Identifying PTC Heater Assembly Connector Terminals
      G04829558Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE PTC HEATER ASSEMBLY  (See DISASSEMBLY )

    OK: GO TO NEXT STEP 

  10. CHECK HARNESS AND CONNECTOR (BATTERY - PTC HEATER RELAY) 
    1. Remove the HTR SUB1 relay from the engine room R/B.
    2. Remove the HTR SUB2 and HTR SUB3 relays from the engine room R/B No. 2.
    3. Measure the voltage.

      Standard voltage 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      HTR SUB1-5-Body ground Always 11 to 14 V
      HTR SUB2-5 - Body ground Always 11 to 14 V
      HTR SUB3-5 - Body ground Always 11 to 14 V
    4. Reinstall the HTR SUB1 relay.
    5. Reinstall the HTR SUB2 and HTR SUB3 relays.
      6. Fig 9: Identifying HTR SUB2 And HTR SUB3 Relays
      G04829556Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  11. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - PTC HEATER ASSEMBLY) 
    1. Remove the HTR SUB1 relay from the engine room R/B.
    2. Remove the HTR SUB2 and HTR SUB3 relays from the engine room R/B No. 2.
    3. Disconnect the A17 PTC heater assembly connector.
    4. Measure the resistance.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Specified Condition
      HTRSUB1-3-A17-2(B) Below 1 Ω
      HTRSUB2-3-A17-3(B) Below 1 Ω
      HTRSUB3-3-A17-1(B) Below 1 Ω
    5. Reinstall the HTR SUB1 relay.
    6. Reinstall the HTR SUB2 and HTR SUB3 relays.
    7. Reconnect the PTC heater assembly connector.
      8. Fig 10: Identifying HTR SUB2 And HTR SUB3 Relays
      G04829560Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE  AIR CONDITIONING AMPLIFIER  

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