AIR SUSPENSION SYSTEM, Diagnostic DTC:C1752/52

DTC Code DTC Name
C1752/52 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 No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

C1752/52

Compressor Motor Malfunction

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

Indicated

WIRING DIAGRAM

C218586E04

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.

Tip:

If DTC C1782/82 is output at the same time as C1752/52, perform the inspection necessary for DTC C1782/82 first (Click here).

PROCEDURE

  1. INSPECT SUSPENSION CONTROL RELAY (AIR SUS)

    1. Turn the engine switch off.

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

    3. C149624C01

      *1

      AIR SUS Relay

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      3 - 5

      12 V battery voltage is not applied to terminal 1 and 2

      10 kΩ or higher

      12 V battery voltage is applied to terminal 1 and 2

      Below 1 Ω

      Result

      Result

      OK

      NG

    NG

    REPLACE SUSPENSION CONTROL RELAY (AIR SUS)

    OK
  2. CHECK TERMINAL VOLTAGE (POWER SUPPLY)

    1. C221184C01

      *a

      Component without AIR SUS Relay

      (Engine Room Relay Block)

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

    2. 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

      Result

      Result

      OK

      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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

    1. Disconnect the S10 height control compressor connector.

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

    3. Disconnect the A11 suspension control ECU connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      S10-1 (B) - Engine room relay block AIR SUS relay terminal 3

      Always

      Below 1 Ω

      S10-1 (B) - Body ground

      Always

      10 kΩ or higher

      S10-2 (E) - Body ground

      Always

      Below 1 Ω

      A11-19 (RM+) - S10-3 (RM+)

      Always

      Below 1 Ω

      A11-19 (RM+) - Body ground

      Always

      10 kΩ or higher

      A11-17 (RM-) - S10-4 (RM-)

      Always

      Below 1 Ω

      A11-17 (RM-) - Body ground

      Always

      10 kΩ or higher

      Result

      Result

      OK

      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK
  4. INSPECT HEIGHT CONTROL COMPRESSOR (COMPRESSOR MOTOR)

    1. C214513C01

      *a

      Component without harness connected

      (Height Control Compressor)

      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 (+) 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.

      Result

      Result

      OK

      NG

    OK

    REPLACE SUSPENSION CONTROL ECU

    NG

    REPLACE HEIGHT CONTROL COMPRESSOR ASSEMBLY