AIR SUSPENSION SYSTEM, Diagnostic DTC:C1783

DTC Code DTC Name
C1783 Speed Signal Communication Error

DESCRIPTION

The speed sensors monitor the speed of the wheels, and send appropriate speed signals to the suspension control ECU through the skid control ECU. If trouble occurs in either the front speed sensor or rear speed sensor, DTC C1783 is output.

DTC No. Detection Condition Trouble Area
C1783 Speed sensor circuit malfunction for 1 second or more.

  • Speed sensor

  • Skid control ECU

  • Suspension control ECU

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. CHECK DTC (AIR SUSPENSION SYSTEM)


    1. Clear the DTC Click here.

    2. Perform a road test.

    3. Check if DTC C1783 and U0122 are output Click here.

      Result
      Result Proceed to
      DTC is not output A
      DTC is output (for LHD) B
      DTC is output (for RHD) C

    B

    GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here

    C

    GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here

    A

  2. CHECK DTC (BRAKE CONTROL SYSTEM)


    1. Check if DTC C1783 and a brake control system speed sensor malfunction DTC (C1235/35, C1236/36, C1238/ 38, C1239/39, C1464/31, C1465/32, C1466/33 or C1467/34) are output Click here.

      Result
      Result Proceed to
      DTC is not output A
      DTC is output B

    B

    GO TO BRAKE CONTROL SYSTEM (DIAGNOSTIC TROUBLE CODE CHART) Click here

    A

  3. CHECK VEHICLE SPEED SIGNAL (DATA LIST)


    1. Turn the power switch OFF.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the power switch ON (IG) and the tester ON.

    4. Enter the following menus: Chassis / Air suspension / Data List.

    5. Using the intelligent tester, read the Data List.

      Air Suspension
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR Wheel Speed

      Front right wheel speed reading /

      min.: 0 km/h (0 mph)

      max.: 255 km/h (158 mph)

      		 Actual vehicle speed Speed indicated on combination meter
      FL Wheel Speed

      Front left wheel speed reading /

      min.: 0 km/h (0 mph)

      max.: 255 km/h (158 mph)

      		 Actual vehicle speed Speed indicated on combination meter
      RR Wheel Speed

      Rear right wheel speed reading /

      min.: 0 km/h (0 mph)

      max.: 255 km/h (158 mph)

      		 Actual vehicle speed Speed indicated on combination meter
      RL Wheel Speed

      Rear left wheel speed reading /

      min.: 0 km/h (0 mph)

      max.: 255 km/h (158 mph)

      		 Actual vehicle speed Speed indicated on combination meter
      OK
      Vehicle speed indicated on the tester indicates the actual speed.
      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

    GO TO BRAKE CONTROL SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here