Code No. C1860: High voltage at ASTC-ECU power supply


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 .).
  • Before replacing the ECU, ensure that the communication circuit is normal.

OPERATION



  • The ASTC-ECU is energized by the ignition switch (IG1) through multi-purpose fuse No.15 and the ASTC-ECU terminal 25.
  • The wheel speed sensors are energised via ASTC-ECU terminal No. 25.

DIAGNOSIS CODE SET CONDITION



PROBABLE CAUSES



  • Battery abnormality
  • ASTC-ECU malfunction
  • Charging system failed

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
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. Diagnosis code recheck after resetting CAN bus lines

Q. Is the diagnosis code No. C1860 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 5.
Charge or replace the battery. Then go to Step 4.

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

Q. Is the check result normal?
Go to Step 5.
Repair or replace the charging system component(s).

STEP 5. Check whether the diagnosis code is reset.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the diagnosis code No. C1860 set?
Replace the hydraulic unit (integrated with ASTC-ECU) (Refer to .). Then go to Step 6.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting, How to Cope with Intermittent Malfunctions .).

STEP 6. Check whether the diagnosis code is reset.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

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