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Inspection Procedure 13: Steering wheel sensor power supply circuit system
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC 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 scan tool (M.U.T.-IIISE) becomes unavailable.
 
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harness and connectors
  • Fusible link malfunction
  • Improper tightening of 12V Starter Battery terminal
  • 12V Starter Battery failure
  • Steering wheel sensor malfunction
 
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Scan tool (M.U.T.-IIISE) other system DTC.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Check if DTC is set in the ETACS-ECU.
Is the DTC 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 (ground terminal) and the body ground
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check of open circuit in ground line between steering wheel sensor connector and body ground.
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.
 
STEP 4. Check of short to power supply, short to ground, and open circuit in IG11 line between steering wheel sensor connector and ETACS-ECU connector.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 5. Retest the system.
Is the communication with scan tool (M.U.T.-IIISE) possible?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
Replace the steering wheel sensor (Refer to ).