ABS
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.
CIRCUIT OPERATION
The ABS-ECU is energized by the valve power supply circuit (terminal No.26). When the power is supplied from the ignition switch (IG1) to the IG1 relay in ETACS-ECU, IG1 relay is turned on. At this time, the valve power supply circuit (terminal No.26) energizes the ABS-ECU.
DTC SET CONDITIONS
This diagnostic trouble code is set when the ABS-ECU power supply voltage is more than 18.0 ± 1.0 volts.
PROBABLE CAUSES
^ Battery failure
^ Battery terminal looseness
^ Fusible link malfunction
^ Damaged wiring harness and connectors
^ ABS-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
^ MB991974: ABS check harness
STEP 1. M.U.T.-III CAN bus diagnostics
Use scan tool to diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the CAN bus lines. On completion, go to Step 2.
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
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
Refer to 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
Refer to 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. 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-01 ABS-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-01 ABS-ECU connector
1) Disconnect the connector, connect special tool ABS check harness (MB991974) to the harness-side connector, and measure the voltage at the special tool connector side.
NOTE: Do not connect the special tool ABS check harness (M8991974) to ABS-ECU.
2) Measure the voltage between terminal No.26 and body ground.
OK: Approximately battery voltage
Q: Is the check result normal?
YES: Go to Step 9.
NO: Repair the wiring harness between A-01 ABS-ECU connector terminal No. 26 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-317 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: Approximately battery 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-317 ETACS-ECU connector
1) Without disconnecting the connector, measure by backprobing.
2) Turn the ignition switch to the ON position.
3) Check the voltage between the terminal No. 5 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-33 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-01 ABS-ECU connector
1) Disconnect the connector, connect the ABS check harness (Special tool: MB991974) to the wiring harness-side connector, and measure at the special tool connector side.
NOTE: Do not connect the special tool to ABS-ECU.
2) Turn the ignition switch to the ON position.
3) Check the voltage between the terminal No. 7 and the body ground.
OK: Approximately battery voltage
Q: Is the check result normal?
YES: Go to Step 15.
NO: Repair the wiring harness between C-317 ETACS-ECU connector terminal No. 5 and A-01 ABS-ECU connector terminal No. 7.
STEP 15. Resistance measurement at A-01 ABS-ECU connector
1) Disconnect the connector, connect the ABS check harness (Special tool: MB991974) to the wiring harness-side connector, and measure at the special tool connector side.
NOTE: Do not connect the special tool to ABS-ECU.
2) Resistance between terminal No.1 and body ground, and between terminal No.14 and body ground.
OK: Continuity exists (2 ohms or less)
Q: Is the check result normal?
YES: Go to Step 16.
NO: Repair the wiring harness.
STEP 16. Check whether the diagnostic trouble code is reset.
Q: Is DTC C2101 set?
YES: Replace the ABS-ECU. Then go to Step 17.
NO: Intermittent malfunction.
STEP 17. Check whether the diagnostic trouble code is reset.
Q: Is DTC C2101 set?
YES: Return to Step 1.
NO: The procedure is complete.