AIR SUSPENSION SYSTEM, Diagnostic DTC:C1752

DTC Code DTC Name
C1752 Compressor Motor Malfunction

DESCRIPTION

When the "up" side of the height control switch is pressed, a signal is sent from terminal RC of the suspension control ECU to switch the AIR SUS relay on. As a result, the relay contacts close and the compressor motor turns on, producing compressed air.

The suspension control ECU detects the amount of current flowing to the compressor motor by means of the differences in potential at terminals RM+ and RM- of the suspension control ECU. In this way, the suspension control ECU monitors the compressor motor circuit for abnormalities.

DTC Code DTC Detection Condition Trouble Area
C1752 With the AIR SUS relay activated, a lock signal of the height control compressor motor is detected for 4 seconds or more.

  • AIR SUS fuse

  • Harness or connector

  • Height control compressor

  • Suspension control ECU

WIRING DIAGRAM

B001FOYE12

CAUTION / NOTICE / HINT

Note


  • When replacing the suspension control ECU, perform registration Click here.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips

If DTC C1782 is output at the same time as C1752, perform the inspection necessary for DTC C1782 first Click here.

PROCEDURE


  1. INSPECT SUSPENSION CONTROL RELAY (AIR SUS)

    Click here


    NG

    REPLACE SUSPENSION CONTROL RELAY (AIR SUS)

    OK

  2. CHECK TERMINAL VOLTAGE (POWER SUPPLY)


    1. Remove the AIR SUS relay from the engine room relay block.

    2. B001HRSC06
      Text in Illustration
      *a

      Component without AIR SUS Relay

      (Engine Room Relay Block)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      Engine room relay block AIR SUS relay terminal 5 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL COMPRESSOR - AIR SUS RELAY/SUSPENSION CONTROL ECU)


    1. Disconnect the S11 height control compressor connector.

    2. Remove the AIR SUS relay from the engine room relay block.

    3. Disconnect the A14 suspension control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      S11-1 (B) - Engine room relay block AIR SUS relay terminal 3 Always Below 1 Ω
      S11-1 (B) - Body ground Always 10 kΩ or higher
      S11-2 (E) - Body ground Always Below 1 Ω
      A14-19 (RM+) - S11-3 (RM+) Always Below 1 Ω
      A14-19 (RM+) - Body ground Always 10 kΩ or higher
      A14-17 (RM-) - S11-4 (RM-) Always Below 1 Ω
      A14-17 (RM-) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT HEIGHT CONTROL COMPRESSOR (COMPRESSOR MOTOR)


    1. Remove the height control compressor Click here.

    2. B001DJNE09
      Text in Illustration
      *a

      Component without harness connected

      (Height Control Compressor)

      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 (+) voltage → Terminal 1 (B)

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

      		 Motor operates

      Note


      • Do not allow the compressor motor to operate for approximately 90 seconds or more.

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


    OK

    REPLACE SUSPENSION CONTROL ECU Click here

    NG

    REPLACE HEIGHT CONTROL COMPRESSOR ASSEMBLY Click here