Inspection Procedure 13: Steering wheel sensor power supply circuit system


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 ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION

  • Steering wheel sensor contains the power supply circuit for Steering wheel sensor. The power is supplied from the ETACS-ECU (IG11 terminal). The power is supplied from the fusible link.
  • When malfunction occurs in steering wheel sensor power supply, the communication with M.U.T.-III becomes unavailable.

PROBABLE CAUSES

  • Damaged wiring harness and connectors
  • Fusible link malfunction
  • Improper tightening of battery terminal
  • Battery failure
  • Charging system failed
  • Steering wheel sensor malfunction

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III other system diagnosis code
Check if diagnosis code is set to the ETACS-ECU.

Q. Is the diagnosis code set?
Troubleshoot the ETACS. Refer to GROUP 54A - ETACS .
Go to Step 2

STEP 2. Resistance measurement at steering wheel sensor connector
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Resistance between the steering wheel sensor connector (earth terminal) and the body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 4
Go to Step 3

STEP 3. Check of open circuit in earth line between steering wheel sensor connector and body earth

Q. Is the check result normal?
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness. Then go to Step 6.

STEP 4. Check of short to power supply, short to earth, and open circuit in IG11 line between steering wheel sensor connector and ETACS-ECU connector

Q. Is the check result normal?
Go to Step 5
Repair the connector(s) or wiring harness. Then go to Step 6.

STEP 5. Retest the system.

Q. Is the communication with M.U.T.-III possible?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
Replace the steering wheel sensor (Refer to ). Then go to Step 6.

STEP 6. Retest the system.

Q. Is the communication with M.U.T.-III possible?
Return to Step 1.
This diagnosis is complete.