DTC C2100: Battery Voltage Malfunction (Low Voltage)

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.
Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION

AWC-ECU power supply is provided from the battery via ETACS-ECU.

DTC SET CONDITIONS

This diagnostic trouble code is set when the abnormality below is detected:

When the AWC-ECU power supply voltage and solenoid valve power supply voltage are 9 V or less.
When ASC-ECU low voltage is detected.

PROBABLE CAUSES

Malfunction of ASC-ECU
Malfunction of the ETACS-ECU
Defective battery
Charging system failed
Damaged harness wires and connectors
Malfunction of AWC-ECU

DIAGNOSTIC PROCEDURE

STEP 1. Scan tool CAN bus diagnostics

Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?

	Go to Step 3.

	Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting .) After repairing the CAN bus line, go to Step 2.

STEP 2. Check whether the DTC is reset.

Q. Is DTC No. C2100 set?

	Go to Step 3.

	This diagnosis is complete.

STEP 3. Scan tool diagnostic trouble code

Check the ASC diagnostic trouble code. (Refer to GROUP 35C - Troubleshooting

Q. Is the DTC set?

	Perform the relevant troubleshooting.

	Go to Step 4.

STEP 4. Scan tool diagnostic trouble code

Check the ETACS diagnostic trouble code. (Refer to GROUP 54A - Troubleshooting

Q. Is the DTC set?

	Perform the relevant troubleshooting.

	Go to Step 5.

STEP 5. Check the battery.

Refer to GROUP 54A - Battery Test

Q. Is the check result normal?

	Go to Step 7.

	Charge or replace the battery. Then go to Step 6.

STEP 6. Check the charging system.

Refer to GROUP 16 - Charging System

Q. Is the check result normal?

	Go to Step 7.

	Repair or replace the charging system component(s).

STEP 7. Voltage measurement at C-46 AWC-ECU connector

Measure the voltage between C-46 AWC-ECU connector terminal No.12 - and the body ground.

OK: Battery positive voltage

Q. Is the check result normal?

	Go to Step 11.

	Go to Step 8.

STEP 8. AWC-ECU connector, ETACS-ECU connector check: C-46, C-315

Q. Is the check result normal?

	Go to Step 9.

	Repair the defective connector. Then go to Step 14.

STEP 9. Check the wiring harness between C-46 AWC-ECU connector terminal No. 12 and C-315 ETACS-ECU connector terminal No.4.

Check the wiring harness for open or short circuit (short to ground).

Q. Is the check result normal?

	Go to Step 10.

	Check C-41 intermediate connector, C-43 J/C (4), C-103 J/C (3). When no problem is found, repair the wiring harness. Then go to Step 14.

STEP 10. Scan tool service data

Item No. 43: Battery voltage (Refer to service data reference table

Q. Is the check result normal?

	Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)

	Replace the ETACS-ECU. (Refer to GROUP 54A - ETACS-ECU .) Then go to Step 14.

STEP 11. AWC-ECU connector check: C-46

Q. Is the check result normal?

	Go to Step 12.

	Repair the defective connector. Then go to Step 14.

STEP 12. Check the wiring harness between C-46 AWC-ECU connector terminal No. 13 and body ground.

Check the wiring harness for open circuit.

Q. Is the check result normal?

	Go to Step 13.

	Repair the wiring harness. Then go to Step 14.

STEP 13. Scan tool service data

Item No. 43: Battery voltage (Refer to service data reference table

Q. Is the check result normal?

	Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)

	Replace the AWC-ECU.(Refer to .) Then go to Step 14.

STEP 14. Check whether the DTC is reset.

Q. Is DTC No. C2100 set?

	Return to Step 1.

	This diagnosis is complete.