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Inspection Procedure 6: Front door lock/unlock switch does not work.
 
 
cautionBefore replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
 
 
PROBABLE CAUSES
  • Malfunction of the keyless operation antenna (Front: Outer side)
  • Malfunction of the lock/unlock switch (front door outside handle)
  • Damaged wiring harness and connectors
  • Malfunction of the KOS&OSS-ECU
  • An ambient electric device or noise source interferes with this system when the lock/unlock switch is operated.
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), check the DTC.
Check if any DTC is set in the KOS&OSS-ECU.
Is the DTC set?
Refer to diagnostic trouble code chart .
: Go to Step 2.
: Go to Step 8.
 
STEP 2. Lock/unlock switch (driver’s side) check
Check that the lock/unlock switch (driver’s side) is normal (Refer to ).
Is the check result normal?
Go to Step 3.
Replace the lock/unlock switch (driver’s side) (Refer to ).
 
STEP 3. Resistance measurement at lock/unlock switch (driver’s side) connector (ground line).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the lock/unlock switch (driver’s side) connector (ground line) and body ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 5.
Go to Step 4.
 
STEP 4. Check of open circuit in ground line between the lock/unlock switch (driver’s side) connector and the 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 wiring harness.
 
STEP 5. Check of short to power supply, short to ground, or open circuit in DRRQ line between the KOS&OSS-ECU connector and the lock/unlock switch (driver’s side) connector.
Is the check result normal?
Go to Step 6.
Repair the wiring harness.
 
STEP 6. Keyless operation system communication test
Using scan tool (M.U.T.-IIISE), perform the antenna communication test to check that the keyless operation antenna (Front: Outer side) communicates normally (Refer to ).
  • DR side antenna (outdoor)
OK: Normal values are displayed for all the items
Is the check result normal?
Go to Step 7.
Perform troubleshooting for DTC B240A (Refer to ).
 
STEP 7. Check of the troubles
Remove commercial electric appliances if they are attached on. Operate the lock/unlock switch (driver’s side) and check that the doors can be locked and unlocked.
Is the check result normal?
Aggravation of radio wave condition caused by commercial electric products or intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace KOS&OSS-ECU and register the ID codes (Refer to ).
 
STEP 8. Lock/unlock switch (passenger’s side) check
Check that the lock/unlock switch (passenger’s side) is normal (Refer to ).
Is the check result normal?
Go to Step 9.
Replace the lock/unlock switch (passenger’s side) (Refer to ).
 
STEP 9. Resistance measurement at lock/unlock switch (passenger’s side) connector (ground line).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the lock/unlock switch (passenger’s side) connector (ground line) and body ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 11.
Go to Step 10.
 
STEP 10. Check of open circuit in ground line between the lock/unlock switch (passenger’s side) connector and the 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 wiring harness.
 
STEP 11. Check of short to power supply, short to ground, or open circuit in ASRQ line between the KOS&OSS-ECU connector and the lock/unlock switch (passenger’s side) connector.
Is the check result normal?
Go to Step 12.
Repair the wiring harness.
 
STEP 12. Keyless operation system communication test
Using scan tool (M.U.T.-IIISE), perform the antenna communication test to check that the keyless operation antenna (Front: Outer side) (Refer to ).
  • PS side antenna(outdoor)
OK: Normal values are displayed for all the items
Is the check result normal?
Go to Step 13.
Perform troubleshooting for DTC B240B (Refer to ).
 
STEP 13. Check of the troubles
Remove commercial electric appliances if they are attached on. Operate the lock/unlock switch (passenger’s side) and check that the doors can be locked and unlocked.
Is the check result normal?
Aggravation of radio wave condition caused by commercial electric products or intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace KOS&OSS-ECU and register the ID codes (Refer to ).