Active Stability Control System (ASC)

DTC C2101: Abnormality in battery voltage (high 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 Initial Inspection and Diagnostic Overview ).
- Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit (integrated with ASC-ECU) is replaced, always perform the calibration of steering wheel sensor, G and yaw rate sensor, brake fluid pressure sensor, cut valve, and inlet valve (Refer to G and Yaw Rate Sensor Calibration , Testing and Inspection , Master Cylinder Brake Fluid Pressure Sensor Calibration , and Testing and Inspection ).

CIRCUIT OPERATION

- ASC-ECU contains the power supply circuit (terminal No. 32) for the solenoid valve. The solenoid valve is energized by the valve relay, which is incorporated in ASC-ECU.
- ASC-ECU contains the power supply circuit (terminal No. 2) for ASC-ECU, and the power is supplied from the fusible link No. 34 through the multi-purpose fuse No. 17.
- The valve relay in ASC-ECU is energized at all times, and the solenoid valve is always energized while the system is in operation unless the initial check is in progress when the ignition switch is turned ON, or unless the periodical system check is in progress.

DTC SET CONDITIONS

This diagnostic trouble code is set when the ASC-ECU power supply voltage and solenoid valve power supply voltage become 18.0 ± 1.0 V or higher.

PROBABLE CAUSES

- Battery failure
- Battery terminal looseness
- Fusible link malfunction
- Damaged wiring harness and connectors
- ASC-ECU malfunction
- Charging system failed

DIAGNOSIS

Required Special Tools:

- MB991958 Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827 M.U.T.-III USB Cable
- MB991910 M.U.T.-III Main Harness A
- MB991997: ASC check harness

STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.

Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?

YES Go to Step 3.
NO Repair the CAN bus lines CAN Bus Diagnostics Chart).
On completion, go to Step 2.
STEP 2. DTC recheck after repairing the CAN bus line

Q. Is DTC C2101 set?

YES Go to Step 3.
NO The procedure is complete.
STEP 3. Battery terminal check

Check that the battery terminal is not loose.

Q. Is the check result normal?

YES Go to Step 4.
NO Securely install the battery terminal. Then go to Step 4.
STEP 4. Battery check

Battery Test.

Q. Is the battery in good condition?

YES Go to Step 6.
NO Charge or replace the battery, and then go to Step 5.
STEP 5. Charging system check

Output Current Test.

Q. Is the charging system in good condition?

YES Go to Step 6.
NO Repair or replace the charging system component(s).
STEP 6. Connector check: A-05 ASC-ECU connector, C-309 ETACS-ECU connector and C-315 ETACS-ECU connector, C-131 intermediate connector

Q. Is the check result normal?

YES Go to Step 7.
NO : Repair the defective connector.
STEP 7. Fusible link check: Check the fusible link No.27.

Check that the fusible link No. 27 is normal and does not exceed the capacity.

Q. Is the check result normal?

YES Go to Step 9.
NO Go to Step 8.
STEP 8. Resistance measurement at A-05 ASC-ECU connector





(1)Disconnect the connector, connect the special tool ASC check harness (MB991997) to the wiring harness-side connector, and then measure the resistance at the special tool connector side.
NOTE:
Do not connect the special tool to ASC-ECU.

(2)Measure the resistance between the terminal No. 32 and the body ground.
OK: No continuity

Q. Is the check result normal?

YES Replace the fusible link No.27. Then go to Step 15.

NO The short circuit may be present in the power supply circuit. Repair the wiring harness between the A-05 ASC-ECU connector terminal No.32 and the fusible link No.27, and then replace the fusible link No.27. Then go to Step 15.

STEP 9. Voltage measurement at the A-05 ASC-ECU connector





(1)Disconnect the connector, connect the special tool ASC check harness (MB991997) to the wiring harness-side connector, and measure the voltage at the special tool connector side.
NOTE:
Do not connect the special tool to ASC-ECU.

(2)Measure the voltage between the terminal No. 32 and the body ground.
OK: Approximately system voltage

Q. Is the check result normal?

YES Go to Step 10.

NO The open circuit may be present in the power supply circuit. Repair the wiring harness between the A-05 ASC-ECU connector terminal No.32 and the fusible link No.27. Then go to Step 15.

STEP 10. Fusible link check: Check the fusible link No. 34.

Check that the fusible link No. 34 is normal and does not exceed the capacity.

Q. Is the check result normal?

YES Go to Step 12.
NO Go to Step 11.
STEP 11. Resistance measurement at C-309 ETACS-ECU connector

(1)Removal the fusible link No.34.

(2)Disconnect the C-309 ETACS-ECU connector, and then measure the resistance at the connector side.

(3)Measure the resistance between the terminal No.1 and the body ground.
OK: No continuity


Q. Is the check result normal?

YES Replace the fusible link No.34. Then go to Step 15.
NO The short circuit may be present in the power supply circuit. Repair the wiring harness between the C-309 ETACS-ECU connector terminal No.1 and the fusible link No.34, and then replace the fusible link No.34. Then go to Step 15.
STEP 12. Resistance measurement at fusible link No.34 and C-309 ETACS-ECU connector

(1)Disconnect the C-309 ETACS-ECU connector and fusible link No.34, and then measure the resistance at the harness connector side.

(2)Measure the resistance between the fusible link No.34 and C-309 ETACS-ECU connector terminal No.1.
OK: Continuity exists (2ohms or less)


Q. Is the check result normal?

YES Go to Step 13.
NO The open circuit may be present in the power supply circuit. Repair the wiring harness between the fusible link No.34 and C-309 ETACS-ECU connector terminal No.1. Then go to Step 15.
STEP 13. Resistance measurement at A-05 ASC-ECU connector





(1)Disconnect the connector, connect the special tool ASC check harness (MB991997) to the wiring harness-side connector, and measure the resistance at the special tool connector side.
NOTE:
Do not connect the special tool to ASC-ECU.

(2)Measure the resistance between the terminal No. 16 and the body ground as well as between the terminal No. 47 and the body ground.
OK: Continuity exists (2ohms or less)

Q. Is the check result normal?

YES Go to Step 14.

NO : Repair the wiring harness.

STEP 14. Check whether the DTC is reset.

Erase the DTC.

Q. Is DTC C2101 set?

YES Replace the hydraulic unit (integrated with ASC-ECU) (Refer to Service and Repair). Then go to Step 15.
NO Intermittent malfunction How to Cope With Intermittent Malfunctions).
STEP 15. Check whether the DTC is reset.

Erase the DTC.

Q. Is DTC C2101 set?

YES Return to Step 1.
NO The procedure is complete.