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 - CAN Bus Diagnostics Table ).

OPERATION
The ASC-ECU power supply energised by the electric motor switch (ONA-14 is transmitted to ASC-ECU (terminal No. 32) through the multi-purpose fuse No. 15.

DIAGNOSIS CODE SET CONDITIONS
Code No. C1860 will be set when the power supply voltage to ASC-ECU has increased to a specified value or higher. Code No. C1861 will be set when the power supply voltage to the ASC-ECU has decreased to a specified value or lower.

PROBABLE CAUSES
Current trouble
  • Damaged wiring harness and connectors
  • Excessive electrical load
  • Battery failure
  • ASC-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.32) to the TCL/ASC-ECU. For diagnosis procedures, refer to How to treat past trouble (GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).

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 Diagnostics 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. Auxiliary battery check
Refer to GROUP 54A - Battery Test .

Q. Is the battery in good condition?
Go to Step 4.
Replace the auxiliary battery. Then go to Step 11.

STEP 4. Charging system check
Check if diagnosis code is set to the OBC.

Q. Is the diagnosis code set?
Troubleshooting the OBC (Refer to GROUP 54D - OBC/Diagnosis Code Chart ). Then go to Step 5.
Go to Step 5.

STEP 5. Connector check: A-14 ASC-ECU connector, B-302 junction block connector, B-306 junction block connector

Q. Is the check result normal?
Go to Step 6.
NO : Repair the defective connector. Then go to Step 11.

STEP 6. Fuse check: Check the fuse No.15.
Visually check for open circuit in the fuse No.15.

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

STEP 7. Resistance measurement at A-14 ASC-ECU connector
(1)Disconnect the ASC-ECU connector, connect special tool ABS check harness (MB992335) 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 (MB992335) to ASC-ECU.
(2)Disconnect the B-306 junction block connector.

(3)Measure the resistance between the A-14 ASC-ECU connector terminal No.32 and the body earth.
OK: No continuity

Q. Is the check result normal?

Replace the fuse No.15. Then go to Step 11.

The short circuit may be present in the power supply circuit. Repair the wiring harness between the A-14 ASC-ECU connector terminal No.32 and B-306 junction block connector terminal No.8, and then replace the fuse No.15. Then go to Step 11.

STEP 8. Voltage measurement at the A-14 TCL/ASC-ECU connector
(1)Disconnect the ASC-ECU connector, connect special tool ABS check harness (MB992335) 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 (MB992335) to ASC-ECU.
(2)Turn the electric motor switch to the "ON" position.

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

Q. Is the check result normal?

Go to Step 9.

The open circuit may be present in the power supply circuit. Repair the wiring harness between the A-14 ASC-ECU connector terminal No.32 and the fuse No.15. Then go to Step 11.

STEP 9. Resistance measurement at A-14 ASC-ECU connector
(1)Disconnect the ASC-ECU connector, connect special tool ABS check harness (MB992335) 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 (MB992335) to ASC-ECU.

(2)Measure the resistance between the terminal No.13 and the body earth, and between the terminal No.38 and the body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 10.

An open circuit may be present in the earth circuit. Repair the wiring harness between the A-14 ASC-ECU connector terminal No.13 and the body earth, and between the A-14 ASC-ECU connector terminal No.38 and the body earth. Then go to Step 11.

STEP 10. 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 ASC-ECU) (Refer to ). Then go to Step 11.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).

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?
Return to Step 1.
This diagnosis is complete.