Code No.C1860: Abnormality In Battery Voltage (High Voltage)
Code No.C1861: Abnormality In Battery Voltage (Low Voltage)




caution If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, Trouble code diagnosis ).

OPERATION
The ABS-ECU is energised by the ignition switch (IG2) through multi-purpose fuse No. 40 and the ABS-ECU (terminal No. 20).

DIAGNOSIS CODE SET CONDITIONS
C1861 will be set when the power supply voltage to the ABS-ECU has decreased to a predetermined value or lower. C1860 will be set when the power supply voltage to the ABS-ECU has increased to a predetermined value or higher.

PROBABLE CAUSES
Current trouble
  • Damaged wiring harness and connectors
  • Excessive electrical load
  • Battery failure
  • ABS-ECU malfunction
  • Charging system failed
Past trouble
  • Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the power supply circuit (terminal No. 20) to the ABS-ECU. For diagnosis procedures, refer to How to treat past trouble (GROUP 00 - How to Cope with Intermittent Malfunction ).

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table ). On completion, go to Step 2.

STEP 2. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No.C1860 or C1861 set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Battery check
Refer to GROUP 54A - Battery Test .

Q. Is the battery in good condition?
Go to Step 4.
Replace the battery. Then go to Step 12.

STEP 4. Charging system check
Refer to GROUP 16 - Charging System .

Q. Is the charging system in good condition?
Go to Step 5.
Repair or replace the charging system component(s). Then go to Step 12.

STEP 5. Connector check: A-05 ABS-ECU connector, B-240 ignition switch connector, B-210 junction block connector, B-229 junction block connector







Q. Is the check result normal?

Go to Step 6.

NO : Repair the defective connector. Then go to Step 12.

STEP 6. Fusible link check: Check the fuse No.40.
Visually check for open circuit in the fusible link No.40.

Q. Is the check result normal?
Go to Step 8.
Go to Step 7.

STEP 7. Resistance measurement at A-05 ABS-ECU connector

(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991951) to the harness-side connector, and then measure the resistance at the special tool connector side.
note Do not connect the special tool ABS check harness (MB991951) to ABS-ECU.
(2)Disconnect the B-210 junction block connector.

(3)Measure the resistance between the A-05 ABS-ECU connector terminal No.20 and the body earth.
OK: No continuity

Q. Is the check result normal?

Replace the fuse No.40. Then go to Step 12.

The short circuit may be present in the power supply circuit. Repair the wiring harness between the A-05 ABS-ECU connector terminal No.20 and B-210 junction block connector terminal No.11, and then replace the fuse No.40. Then go to Step 12.

STEP 8. Voltage measurement at the B-229 junction block connector


(1)Disconnect the B-229 junction block connector, and then measure the voltage at the harness connector side.
(2)Ignition switch to the "ON" position.
(3)Measure the voltage between the terminal No.3 and the body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 9.

The short circuit may be present in the power supply circuit. Repair the wiring harness between the B-229 junction block connector terminal No.3 and B-240 ignition switch connector terminal No.2. Then go to Step 12.

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

(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991951) to the harness-side connector, and then measure the voltage at the special tool connector side.
note Do not connect the special tool ABS check harness (MB991951) to ABS-ECU.
(2)Ignition switch to the "ON" position.

(3)Measure the voltage between the terminal No.20 and the body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 10.

The open circuit may be present in the power supply circuit. Repair the wiring harness between the A-05 ABS-ECU connector terminal No.20 and the B-210 junction block connector terminal No.11. Then go to Step 12.

STEP 10. Resistance measurement at A-05 ABS-ECU connector

(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991951) to the harness-side connector, and then measure the resistance at the special tool connector side.
note Do not connect the special tool ABS check harness (MB991951) to ABS-ECU.

(2)Measure the resistance between the terminal No.23 and the body earth, and between the terminal No.26 and the body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 11.

An open circuit may be present in the earth circuit. Repair the wiring harness between the A-05 ABS-ECU connector terminal No.23 and the body earth, and between the A-05 ABS-ECU connector terminal No.26 and the body earth. Then go to Step 12.

STEP 11. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Drive the vehicle at 6 km/h or more.

Q. Is the diagnosis code No.C1860 or C1861 set?
Replace the hydraulic unit (integrated with ABS-ECU) (Refer to ). Then go to Step 12.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 12. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Drive the vehicle at 6 km/h or more.

Q. Is the diagnosis code No.C1860 or C1861 set?
Return to Step 1.
This diagnosis is complete.