Electronic Control AWD

DTC C2101: Abnormal battery voltage (Too high)









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

AWD-ECU detects a power supply voltage abnormal increase, and if any abnormality occurs, it interrupts the system.

DTC SET CONDITIONS

If the following conditions are met when the system is activated, AWD-ECU gradually switches the control from AWD to FWD, flashes the AWD/LOCK indicators alternately, and sets the DTC C2101.

- IG1 voltage: More than 17 V

- Voltage between the battery and ETACS-ECU: More than 17 V

TROUBLESHOOTING HINTS

Current trouble

- Damaged wiring harness and connectors
- High-voltage short-circuit between the battery and AWD-ECU

- Malfunction of generator or other power supply systems
Past trouble

- Intermittent wiring harness or connector failure
NOTE:
For diagnosis procedures, refer to "How to treat past trouble" How to Treat Past Trouble).

- Malfunction of generator or other power supply systems

DIAGNOSIS

Required Special Tools:

- 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. Battery voltage check

Check the battery voltage.

Q. Is the check result normal?

YES Go to Step 2.
NO Charge or replace the battery.
STEP 2. Generator output current check

Check if the generator is correctly operated Generator Output Line Voltage Drop Test).

Q. Is the check result normal?

YES Go to Step 3.
NO Replace the generator.
STEP 3. Voltage measurement at the ETACS-ECU connector

(1)Disconnect the C-309 ETACS-ECU connector.

(2)Measure the voltage between the C-309 harness side connector terminal No.1 and the body ground.
OK: System voltage


Q. Is the check result normal?

YES Go to Step 5.
NO Go to Step 4.
STEP 4. Wiring harness check

Check the wiring harness between the battery and the C-309 ETACS-ECU connector for damage or other problem.

Q. Is the wiring harness in good condition?

YES Go to Step 8.
NO Repair damage or other problem in the wiring harness. Then go to Step 8.
STEP 5. 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 7.
NO Repair the CAN bus line CAN Bus Diagnostics Chart). On completion, go to Step 6.
STEP 6. 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 C2101 set?

YES Go to Step 7.
NO The procedure is complete.
STEP 7. 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 C2101 set?

YES Replace AWD-ECU (Refer to Service and Repair). Then go to Step 8 .
NO The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
STEP 8. 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 C2101 set?

YES Diagnose again from Step 1.
NO The procedure is complete.