Code No. C1266: Motor stuck
Code No. C1271: Motor drive circuit
Code No. C1273: Motor drive circuit stuck off
Code No. C1274: Motor drive circuit stuck on



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 - Troubleshooting ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the hydraulic unit assembly (integrated with ASTC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G sensor (Refer to ).

OPERATION




DIAGNOSIS CODE SET CONDITIONS


These diagnosis codes will be set under the cases below.
Code No. C1266 Motor stuck
Code No. C1271 Motor drive circuit
Code No. C1273 Motor drive circuit stuck off
Code No. C1274 Motor drive circuit stuck on

PROBABLE CAUSES


Current trouble
Past trouble

DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III CAN bus diagnosis


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

Q. Is the check result normal?

Go to Step 3.
Repair the CAN bus line (Refer to GROUP 54C - CAN Bus Trouble Symptom Chart ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines


Q. Is diagnosis code No. C1266, C1271, C1273 or C1274 set?

Go to Step 3.
This diagnosis is complete.

STEP 3. Check the battery.


Refer to GROUP 54A - Battery Test .

Q. Is the battery in good condition?

Go to Step 4.
Charge or replace the battery. Then go to Step 7.

STEP 4. Measure the resistance at the ASTC-ECU connector.


(1)Connector check: ASTC-ECU connector
(2)Disconnect the connector and measure at the wiring harness side.
(3)Measure the resistance between +BM terminal and body earth.
OK: No continuity

Q. Is the check result normal?

Go to Step 5.
The power supply circuit may be short. Repair the wiring harness wires or connectors between the ACS-ECU connector +BM terminal and the fusible links, or replace the fusible links. Then go to Step 7.

STEP 5. Measure the voltage at the ASTC-ECU connector.


(1)Disconnect the connector and measure at the wiring harness side.
(2)Measure the voltage between +BM terminal and body earth.
OK: Battery voltage

Q. Is the check result normal?

Go to Step 6.
The power supply circuit may be open. Repair the wiring harness wires or connectors between the ACS-ECU connector +BM terminal and the fusible links. Then go to Step 7 .

STEP 6. Measure the resistance at the ASTC-ECU connector.


(1)Disconnect the connector and measure at the wiring harness side.
(2)Measure the resistance between terminals GND1 or GND2 and body earth.
OK: Continuity exists (2 Ω or less).

Q. Is the check result normal?

Go to Step 7.
An open circuit may be present in the earth circuit. Repair the wiring harness wires between ASTC-ECU connector terminal GND1 or GND2 and body earth. Then go to Step 7.

STEP 7. Diagnosis code recheck


Check again if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Ignition switch: "LOCK" (OFF) position to "ON"
(3)Drive the vehicle until the vehicles speed reaches 20 km/h.

Q. Is diagnosis code No. C1266, C1271, C1273 or C1274 set?

Replace the hydraulic unit assembly (integrated with ASTC-ECU) (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).





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