C123B

DTC C123B: Prolonged operation of ASC

CAUTION: If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.

CIRCUIT OPERATION
ASC-ECU controls ASC by calculating the data sent from the wheel speed sensor, the steering wheel sensor, and the G and yaw rate sensor.

DTC SET CONDITIONS
This diagnostic trouble code is set when ASC operates for a prolonged period.

NOTE: When the vehicle runs on a slippery or rough road, or when the vehicle makes the steady turn, this diagnostic trouble code may be set.

PROBABLE CAUSES
^ Malfunction of wheel speed sensor
^ Steering wheel sensor malfunction
^ G and yaw rate sensor malfunction
^ Improper installation of wheel speed sensor, steering wheel sensor, or G and yaw rate sensor
^ ASC-ECU malfunction

DIAGNOSIS

Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. M.U.T.-III CAN bus diagnostics
Use scan tool to diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the CAN bus lines. On completion, go to Step 2.

STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Q: Is DTC C123B set?
YES: Go to Step 3.
NO: The procedure is complete.

STEP 3. M.U.T.-III diagnostic trouble code
Check that DTCs C100A, C1015, C1020, C102B, C1011, C101C, C1027, C1032, C1014, C101F, C102A, C1035, C1041, C1042, C1043, C1044, C1219, C2205, C123C, and C2204 are also set.
Q: Are DTCs C100A, C1015, C1020, C102B, C1011, C101C, C1027, C1032, C1014, C101F, C102A, C1035, C1041, C1042, C1043, C1044, C1219, C2205, C123C, and C2204 also set?
YES: Carry out the diagnosis for the relevant diagnostic trouble codes, and then go to Step 4.
NO: Go to Step 4.

STEP 4. Check whether the diagnostic trouble code is reset.
Q: Is DTC C123B set?
YES: Replace the ASC-ECU.
NO: Intermittent malfunction.