AIR SUSPENSION SYSTEM, Diagnostic DTC:C1752

DTC Code DTC Name
C1752 Height Control Compressor Motor Circuit Malfunction

DESCRIPTION

The signal from the suspension control ECU turns on the suspension control relay. At that time, auxiliary battery voltage is input to the height control compressor motor through the suspension control relay. The height control compressor motor starts.

DTC No. Detection Condition Trouble Area
C1752 With the suspension control relay activated, a lock signal of the height control compressor motor is detected for 4 seconds or more.

  • Suspension control relay

  • Height control compressor (compressor motor)

  • Harness or connector

  • Suspension control ECU

WIRING DIAGRAM

A01H1A3E05

INSPECTION PROCEDURE

Note


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

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

  • If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed Click here.

PROCEDURE


  1. INSPECT SUSPENSION CONTROL RELAY (AIR SUS)


    1. Turn the power switch OFF.

    2. A01GXC2E11

      Remove the suspension control relay from the engine room No. 5 relay block.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      3 - 5 When 12 V battery voltage is not applied to terminal 1 and 2 10 kΩ or higher
      When 12 V battery voltage is applied to terminal 1 and 2 Below 1 Ω

    NG

    REPLACE SUSPENSION CONTROL RELAY

    OK

  2. CHECK HARNESS AND CONNECTOR (COMPRESSOR - ECU, AUXILIARY BATTERY AND BODY GROUND)


    1. A01GZ49E01

      Remove the suspension control relay from the engine room No. 5 relay block.

    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Condition Specified Condition
      Relay block suspension control relay terminal 5 - Body ground Always 11 to 14 V

    3. Disconnect the A57 compressor connector.

      A01H1REE01

    4. Disconnect the A39 ECU connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      Relay block suspension control relay terminal 3 - A57-1 (B) Always Below 1 Ω
      Relay block suspension control relay terminal 3 or A57-1 (B) - Body ground Always 10 kΩ or higher
      A57-2 (E) - Body ground Always Below 1 Ω
      A57-3 (RM+) - A39-17 (RM+) Always Below 1 Ω
      A57-3 (RM+) or A39-17 (RM+) - Body ground Always 10 kΩ or higher
      A57-4 (RM-) - A39-18 (RM-) Always Below 1 Ω
      A57-4 (RM-) or A39-18 (RM-) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT HEIGHT CONTROL COMPRESSOR (COMPRESSOR MOTOR)


    1. A01GXVJE03

      Remove the height control compressor Click here.

    2. Apply 12 V battery voltage to the compressor motor and check the operation of the motor.

      OK
      Measurement Condition Specified Condition

      12 V battery positive (+) → Terminal 1 (B)

      12 V battery negative (-) → Terminal 2 (E)

      		 Motor operates

      Note


      • Do not allow the motor to operate for approximately 60 seconds or more.

      • If the compressor is shorted, locked, or has a similar type of malfunction, a large amount of current will be flowing. Therefore, if the motor does not operate, immediately stop this inspection.

      Result
      Result Proceed to
      NG A
      OK (for LHD) B
      OK (for RHD) C

    B

    REPLACE SUSPENSION CONTROL ECU Click here

    C

    REPLACE SUSPENSION CONTROL ECU Click here

    A

    REPLACE HEIGHT CONTROL COMPRESSOR Click here