Active Skid 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.
^ 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.
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
^ 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. After repairing the CAN bus line, 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
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
Q: Is the charging system in good condition?
YES: Go to Step 6.
NO: Repair or replace the charging system component(s).
STEP 6. Fusible link check: Check the fusible link No.27 and No.34.
Check that the fusible link No. 27 and No. 34 are normal and does not exceed the capacity.
Q: Is the check result normal?
YES: Go to Step 7.
NO: Replace the fusible link No.27 or No.34.
STEP 7. Connector check: A-05 ASC-ECU connector
Q: Is the check result normal?
YES: Go to Step 8.
NO: Repair the defective connector.
STEP 8. Voltage measurement at the A-05 ASC-ECU connector
1) Disconnect the connector, connect the ASC check harness (Special tool: 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: System voltage
Q: Is the check result normal?
YES: Go to Step 9.
NO: Repair the wiring harness between A-05 ASC-ECU connector terminal No. 32 and the fusible link No. 27.
STEP 9. Check of fuse No. 17
Check that the fuse No. 17 is normal and does not exceed the capacity.
Q: Is the check result normal?
YES: Go to Step 10.
NO: Replace the fuse No. 17.
STEP 10. Connector check: C-309 ETACS-ECU connector and C-315 ETACS-ECU connector
Q: Is the check result normal?
YES: Go to Step 11.
NO: Repair the defective connector.
STEP 11. Voltage measurement at the C-309 ETACS-ECU connector
1) Disconnect the connector, and measure at the wiring harness-side connector.
2) Measure the voltage between the terminal No. 1 and the body ground.
OK: System voltage
Q: Is the check result normal?
YES: Go to Step 12.
NO: Repair the wiring harness between C-309 ETACS-ECU connector terminal No. 1 and the fusible link No. 34.
STEP 12. Voltage measurement at the C-315 ETACS-ECU connector
1) Without disconnecting the connector, measure by backprobing.
2) Measure the voltage between the terminal No. 4 and the body ground.
OK: System voltage
Q: Is the check result normal?
YES: Go to Step 13.
NO: Replace the ETACS-ECU. Then go to Step 17.
STEP 13. Connector check: C-103 joint connector, C-130 intermediate connector
Q: Is the check result normal?
YES: Go to Step 14.
NO: Repair the defective connector.
STEP 14. Voltage measurement at the A-05 ASC-ECU connector
1) Disconnect the connector, connect the ABS check harness (Special tool: 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. 2 and the body ground.
OK: System voltage
Q: Is the check result normal?
YES: Go to Step 15.
NO: Repair the wiring harness between C-315 ETACS-ECU connector terminal No. 4 and A-05 ASC-ECU connector terminal No. 2.
STEP 15. Resistance measurement at A-05 ASC-ECU connector
1) Disconnect the connector, connect the ABS check harness (Special tool: 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 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 (2 C2 or less)
Q: Is the check result normal?
YES: Go to Step 16.
NO: Repair the wiring harness.
STEP 16. Check whether the DTC is reset.
Q: Is DTC C2101 set?
YES: Replace the hydraulic unit (incorporates in ASC-ECU). Then go to Step 17.
NO: Intermittent malfunction.
STEP 17. Check whether the DTC is reset.
Q: Is DTC C2101 set?
YES: Return to Step 1.
NO: The procedure is complete.