Electronic Control AWD
DTC C2100: Abnormal battery voltage (Too low)
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 drop, 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 C2100.
- IG1 voltage: Less than 8 V
- Voltage between the battery and ETACS-ECU: Less than 8 V
- Engine speed: more than 1500 r/min
TROUBLESHOOTING HINTS
Current trouble
- Damaged wiring harness and connectors
- Short to ground or open circuit between the battery and AWD-ECU
Past trouble
- Intermittent wiring harness or connector failure
NOTE:
For diagnosis procedures, refer to "How to treat past trouble" How to Treat Past Trouble).
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. 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 4.
NO Go to Step 3.
STEP 3. 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 12.
NO Repair damage or other problem in the wiring harness. Then go to Step 12.
STEP 4. 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 6.
NO Repair the CAN bus line CAN Bus Diagnostics Chart). On completion, go to Step 5.
STEP 5. 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)Start the engine, and continue to run at 1500 r/min or more.
(4)Check if the DTC is set.
Q. Is the DTC C2100 set?
YES Go to Step 6.
NO The procedure is complete.
STEP 6. Check the following connector:
Check the connectors below for improper engagement, terminal damage or terminal drawn in the connector case.
- C-57 AWD-ECU connector
- C-309, C-315 ETACS-ECU connector
- D-51 intermediate connector
- C-36 intermediate connector
- D-52 joint connector (2)
Q. Are the connectors and terminals in good condition?
YES Go to Step 7.
NO Repair the connector(s) or terminal(s). Then go to Step 12.
STEP 7. Wiring harness check
Check the wiring harness between the C-57 AWD-ECU connector and the C-315 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 12.
STEP 8. Voltage measurement at the AWD-ECU connector
(1)Disconnect the C-57 AWD-ECU connector.
(2)Measure the voltage between the C-57 wiring harness side connector terminals No.3, No. 4 (Ignition switch "ON") and the body ground.
OK: System voltage
Q. Is the check result normal?
YES Go to Step 9.
NO Go to Step 10.
STEP 9. Wiring harness check
Check the wiring harness between the C-57 AWD-ECU connector (terminal No.10) and the body ground for damage or other problem.
Q. Is the wiring harness in good condition?
YES Go to Step 11.
NO Repair the wiring harness. Then go to Step 12.
STEP 10. Wiring harness check
Check the wiring harness between the C-57 AWD-ECU connector (terminal No.3) and the C-315 ETACS-ECU connector (terminal No.4), and the wiring harness between the C-57 AWD-ECU connector (terminal No.4) and the C-313 ETACS-ECU connector (terminal No.2) for damage or other problem.
Q. Is the wiring harness in good condition?
YES Go to Step 11.
NO Repair the wiring harness. Then go to Step 12.
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)Start the engine, and continue to run at 1500 r/min or more.
(4)Check if the DTC is set.
Q. Is the DTC C2100 set?
YES Replace AWD-ECU (Refer to Electronic Control AWD). Then go to Step 12.
NO The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
STEP 12. 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)Start the engine, and continue to run at 1500 r/min or more.
(4)Check if the DTC is set.
Q. Is the DTC C2100 set?
YES Diagnose again from Step 1.
NO The procedure is complete.