C145F

DTC C145F: Coupling Overload

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

OPERATION
If AWD-ECU determines that the vehicle is used under some severe operational conditions (such as a long-time driving in AWD on a sandy road, slushy road or road with deep snows or towing or long hill-climbing), AWD-ECU detects the overload to the coupling. If abnormal overload is detected, AWD-ECU interrupts the system to prevent it from being damaged.

DTC SET CONDITIONS
If the following conditions are met, AWD-ECU gradually switches the control from AWD to FWD, makes the drive system fluid temperature warning lamp illuminate, and sets the DTC No. C145F.

^ Drive mode selector: AWD or LOCK
^ When the load to the electronic control coupling is large, the mode is switched to the FWD mode.

TROUBLESHOOTING HINTS

Current trouble
^ The driving conditions are severe.
^ Electronic control coupling failure (clutch slippage)
^ AWD-ECU malfunction
^ Abnormality in ABS wheel speed signal
^ Abnormality in torque command value from the ASC-ECU

Past trouble
^ The past driving conditions were severe.
^ Electronic control coupling intermittent failure (clutch slippage)
^ Abnormality in ABS wheel speed signal
^ Abnormality in torque command value from the ASC-ECU

DIAGNOSIS
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. Scan tool MB991958 CAN bus diagnostics
Use scan tool MB991958 to diagnose the CAN bus lines.

Q:Is the check result normal?
YES: Go to Step 4.
NO: Repair the CAN bus line. On completion, go to Step 2.

STEP 2. Check whether the DTC is reset after repairing the CAN bus line.
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF) position to the ON position.
(3) Check if the DTC is set.

Q:Is the DTC No. C145F set?
YES: Go to Step 3.
NO: This diagnosis is complete.

STEP 3. Scan tool MB991958 DTC of other systems
Check the following service data.

^ Item 07: CAN system (ABS/ASC)
^ Item 16: FL wheel speed sensor
^ Item 17: FR wheel speed sensor
^ Item 18: RL wheel speed sensor
^ Item 19: RR wheel speed sensor

Q:Is the DTC set?
YES: Troubleshoot the ABS system.
NO: Go to Step 4.

STEP 4. Scan tool MB991958 actuator test
On a chassis dynamometer test, use M.U.T.-III to forcibly activate the electronic control coupling from 600 Nm to 730 Nm (443 to 538 ft-lb) in 10 Nm (7.3 ft-lb) steps.

Or on a test run of the vehicle, turn fully the steering wheel (lock condition) and use M.U.T.-III to forcibly activate the electronic control coupling at 500 Nm (368 ft-lb). Then drive the vehicle forward (or back) at about 10 km/h (6.2 mph). If the system is normal, tight cornering phenomenon should occur.

^ Item 01: AWD coupling control torque

Q:Does the electronic control coupling transfer the torque correctly?
YES: Go to Step 5.
NO: Replace the electronic control coupling. Then go to Step 6.

STEP 5. Check whether the DTC is reset.
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF) position to the ON position.
(3) Check if the DTC is set.

Q:Is the DTC No. C145F set?
YES: Replace AWD-ECU. Then go to Step 6.
NO: The code may be set because of some severe operational conditions such as a long-time high speed driving or long hill-climbing in AWD condition.

STEP 6. Check whether the DTC is reset.

Q:Is the DTC No. C145F set?
YES: Diagnose again from Step 1.
NO: This diagnosis is complete.