AIR SUSPENSION SYSTEM, Diagnostic DTC:C1761

DTC Code DTC Name
C1761 Continuous Electric Current to Height Control Compressor Motor

DESCRIPTION

The signal from the suspension control ECU operates the AIR SUS relay and the height control compressor motor starts. The height control compressor motor operates until the targeted vehicle height is reached. Then the height control sensor sends the signal to the suspension control ECU, and stops the height control compressor motor.

DTC No. DTC Detection Condition Trouble Area
C1761 While AIR SUS relay is ON, vehicle height does not reach target for 3 minutes or more

  • Air leakage from the air tube or each valve

  • Height control valve No. 1

  • Height control valve No. 2

  • Height control compressor assembly (Exhaust valve)

  • Pneumatic tank assembly (Low pressure tank valve)

  • Height control compressor assembly (Compressor motor)

  • AIR SUS relay

  • Wire harness or connector

  • Suspension control ECU

INSPECTION PROCEDURE

Note


  • Before performing troubleshooting, inspect the connectors of related circuits.

  • If DTC C1782 (Power Source Voltage Malfunction) is output at the same time, perform troubleshooting for C1782 first Click here.

  • Before replacing the suspension control ECU, perform all of the following again: 1) symptom simulation Click here; 2) DTC inspection Click here; and 3) Intelligent tester inspection (Data List or Active Test) Click here. If no malfunctions are found in other areas, replace the suspension control ECU.

  • If the suspension control ECU is replaced, the vehicle height offset calibration and registration of vehicle identification information must be performed Click here and Click here

PROCEDURE


  1. CUSTOMER PROBLEM ANALYSIS


    1. Ask the customer about the vehicle and usage conditions when the DTC was stored.

      Tech Tips

      DTC 1761 can be stored under unusual vehicle or usage conditions.

      Points to confirm

      • Confirm if there were any foreign objects caught between the body and tires.

      • Confirm if the vehicle has been driven on an unpaved surface or with a wheel not contacting the ground.

      • Confirm if the vehicle has been raised with an excess load.

      • Confirm if the vehicle height mode has been continuously changed using the height control switch, causing the vehicle to raise and lower repeatedly.

    NEXT

  2. CHECK DTC


    1. Clear the DTC Click here.

    2. Turn the power switch on (READY) and wait for 4 minutes or more.

    3. Select luggage mode.

    4. Select HI mode.

    5. Check the DTC Click here.

      Result
      Result Proceed to
      DTC C1761 is output A
      DTC C1761 is not output B
      DTC C1761 and other DTCs are output C

    B

    END (C1761 WAS OUTPUT DUE TO UNUSUAL VEHICLE OR USAGE CONDITION)

    C

    GO TO DTC CHART

    A

  3. INSPECT AIR TUBE FOR AIR LEAK OR CLOG


    1. Inspect the air tube for air leaks or clogs Click here.

      OK
      No air leaks or clogs are found in the air tube.

    NG

    REPAIR OR REPLACE AIR TUBE

    OK

  4. INSPECT HEIGHT CONTROL VALVE NO. 1


    1. Turn the power switch off.

    2. A01NGF7E25
      Text in Illustration
      *1

      Component without harness connected

      (Height Control Valve No. 1)

      Disconnect the height control valve No. 1 connector.

    3. Measure the resistance according to the values in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      3 (RH+) - 2 (E) 15 to 25°C (59 to 77°F) 10 to 14 Ω
      1 (LH+) - 2 (E) 15 to 25°C (59 to 77°F) 10 to 14 Ω

    4. Check the front RH valve.


      1. Connect a positive (+) lead from the battery to terminal 3 (RH+) and a negative (-) lead to terminal 2 (E).

      2. Check the operating sound of the height control valve No. 1.

        OK
        It makes an operating sound (click).

    5. Check the front LH valve.


      1. Connect a positive (+) lead from the battery to terminal 1 (LH+) and a negative (-) lead to terminal 2 (E).

      2. Check the operating sound of the height control valve No. 1.

        OK
        It makes an operating sound (click).

    NG

    REPLACE HEIGHT CONTROL VALVE NO. 1 Click here

    OK

  5. INSPECT HEIGHT CONTROL VALVE NO. 2


    1. Turn the power switch off.

    2. A01NGF7E26
      Text in Illustration
      *1

      Component without harness connected

      (Height Control Valve No. 2)

      Disconnect the rear height control valve No. 2 connector.

    3. Measure the resistance according to the values in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      1 (RH+) - 2 (E) 15 to 25°C (59 to 77°F) 10 to 14 Ω
      3 (LH+) - 2 (E) 15 to 25°C (59 to 77°F) 10 to 14 Ω

    4. Check the rear RH valve.


      1. Connect a positive (+) lead from the battery to terminal 1 (RH+) and a negative (-) lead to terminal 2 (E).

      2. Check the operating sound of the height control valve No. 2.

        OK
        It makes an operating sound (click).

    5. Check the rear LH valve.


      1. Connect a positive (+) lead from the battery to terminal 3 (LH+) and a negative (-) lead to terminal 2 (E).

      2. Check the operating sound of the height control valve No. 2.

        OK
        It makes an operating sound (click).

    NG

    REPLACE HEIGHT CONTROL VALVE NO. 2 Click here

    OK

  6. INSPECT HEIGHT CONTROL COMPRESSOR ASSEMBLY (EXHAUST VALVE)


    1. Turn the power switch off.

    2. A01NHQXE08
      Text in Illustration
      *1

      Component without harness connected

      (Exhaust Valve)

      Disconnect the exhaust valve connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      2 (B) - 1 (L) 15 to 25°C (59 to 77°F) 10 to 14 Ω

    4. Inspect if exhaust valve is stuck:


      1. Connect a positive (+) lead from the battery to terminal 2 (B) and a negative (-) lead to terminal 1 (L).

      2. Check the operating sound of the exhaust valve.

        OK
        It makes an operating sound (click).

    NG

    REPLACE HEIGHT CONTROL COMPRESSOR ASSEMBLY Click here

    OK

  7. INSPECT PNEUMATIC W/TUBE TANK ASSEMBLY (LOW PRESSURE TANK VALVE)


    1. Turn the power switch off.

    2. A01NHQXE09
      Text in Illustration
      *1

      Component without harness connected

      (Low Pressure Tank Valve)

      Disconnect the low pressure tank valve connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      2 (B) - 1 (L) 15 to 25°C (59 to 77°F) 10 to 14 Ω

    4. Inspect if the low pressure tank valve is stuck :


      1. Connect a positive (+) lead from the battery to terminal 2 (B) and a negative (-) lead to terminal 1 (L).

      2. Check the operating sound of the low pressure tank valve.

        OK
        It makes an operating sound (click).

    NG

    REPLACE PNEUMATIC W/TUBE TANK ASSEMBLY Click here

    OK

  8. INSPECT HEIGHT CONTROL COMPRESSOR ASSEMBLY (COMPRESSOR MOTOR)


    1. Turn the power switch off.

    2. Disconnect the compressor motor connector.

    3. A01NG6NE03
      Text in Illustration
      *1

      Component without harness connected

      (Compressor Motor)

      Connect a positive (+) lead from the battery to terminal 1 (B) and a negative (-) lead to terminal 2 (E).

    4. Check the operating of the compressor motor.

      OK
      Motor operates

      Note


      • Do not operate the height control compressor for 60 seconds or more.

      • Since a short and a lock-up inside the height control compressor cause excessive current to flow, stop operation immediately when it does not rotate.


    NG

    REPLACE HEIGHT CONTROL COMPRESSOR ASSEMBLY Click here

    OK

  9. INSPECT AIR SUS RELAY


    1. Turn the power switch off.

    2. A01NDCGE01

      Remove the AIR SUS relay from the engine room J/B.

    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      3 - 5 When battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      When battery voltage is applied between terminals 1 and 2 Below 1 Ω
      Result
      Condition Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    B

    REPLACE SUSPENSION CONTROL ECU (for RHD) Click here

    C

    REPLACE AIR SUS RELAY

    A

    REPLACE SUSPENSION CONTROL ECU (for LHD) Click here