Electronic Control
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 No. 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 alternator or other power supply systems
Past trouble
^ Intermittent wiring harness or connector failure
NOTE: For diagnosis procedures, refer to "How to treat past trouble".
^ Malfunction of alternator or other power supply systems
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. 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.
Q:Is the check result normal?
YES: Go to Step 3.
NO: Replace the alternator.
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 earth.
OK: Battery 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 5.
NO: Repair damage or other problem in the wiring harness. Then go to Step 11.
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. 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 No. C2101 set?
YES: Go to Step 7.
NO: This diagnosis is complete.
STEP 7. Check the following connector:
Check the connectors below for improper engagement, terminal damage or terminal drawn in the connector case.
^ C-128 AWD-ECU connector
^ C-309, C-315 ETACS-ECU connector
^ C-31 intermediate connector
Q:Are the connectors and terminals in good condition?
YES: Go to Step 8.
NO: Repair the connector(s) or terminal(s). Then go to Step 11.
STEP 8. Voltage measurement at the AWD-ECU connector
(1) Disconnect the C-128 AWD-ECU connector.
(2) Measure the voltage between the C-128 wiring harness side connector terminals No.3, No.4 (Ignition switch "ON") and No.10.
OK: Battery voltage
Q:Is the check result normal?
YES: Go to Step 10.
NO: Go to Step 9.
STEP 9. Wiring harness check
Check the wiring harness between the C-128 AWD-ECU connector (terminal No.3 and No.4) and the C-309 ETACS-ECU connector (terminal No.1) for damage or other problem.
Q:Is the wiring harness in good condition?
YES: Go to Step 10.
NO: Repair the wiring harness. Then go to Step 11.
STEP 10. 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. C2101 set?
YES: Replace AWD-ECU. Then go to Step 11.
NO: The trouble can be an intermittent malfunction.
STEP 11. 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. C2101 set?
YES: Diagnose again from Step 1.
NO: This diagnosis is complete.