Inspection Procedure 1: Front door lock/unlock switch does not work. <Vehicles for LHD>
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Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
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PROBABLE CAUSES
- Malfunction of the outside transmission antenna assembly (driver’s side)
- Malfunction of the outside transmission antenna assembly (passenger’s side)
- Malfunction of the lock/unlock switch (driver’s side)
- Malfunction of the lock/unlock switch (passenger’s side)
- 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 PROCEDURE
STEP 1. M.U.T.-III diagnosis code
Check if any diagnosis code is set in the KOS&OSS-ECU.
Q.
Is the diagnosis code set?
Refer to diagnosis code chart.
NO (does not work on the driver’s side)
: Go to Step 2.
NO (does not work on the passenger’s side) : Go to Step 9.
STEP 2. Lock/unlock switch (driver’s side) check
Check that the lock/unlock switch (driver’s side) is normal.
Q.
Is the check result normal?
Go to Step 3.
Replace the lock/unlock switch (driver’s side).
STEP 3. Resistance measurement at lock/unlock switch (driver’s side) connector (earth line)
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the lock/unlock switch (driver’s side) connector (earth line) and body earth.
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
Go to Step 5.
Go to Step 4.
STEP 4. Check of open circuit in earth line between the lock/unlock switch (driver’s side) connector and the 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 wiring harness.
STEP 5. Check of short to power supply, short to earth, or open circuit in DRRQ line between the KOS&OSS-ECU connector and the lock/unlock switch (driver’s side) connector
Q.
Is the check result normal?
Go to Step 6.
Repair the wiring harness.
STEP 6. Keyless operation system communication test
Using M.U.T.-III, perform the antenna communication test to check that the outside transmission antenna assembly (driver’s side) communicates normally.
- Outside transmission antenna assembly (LH)
OK: Normal values are displayed for all the items
Q.
Is the check result normal?
Go to Step 7.
Perform troubleshooting for diagnosis code No. B240A.
STEP 7. Connection check of commercial electric products
Check whether commercial electric products are connected.
Q.
Are commercial electric products connected?
Disconnect the commercial electric products as they may be interfering with communication. Then go to Step 8.
Go to Step 8.
STEP 8. Check of the troubles
Operate the lock/unlock switch (driver’s side) and check that the doors can be locked and unlocked.
Q.
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.
STEP 9. Lock/unlock switch (passenger’s side) check
Check that the lock/unlock switch (passenger’s side) is normal.
Q.
Is the check result normal?
Go to Step 10.
Replace the lock/unlock switch (passenger’s side).
STEP 10. Resistance measurement at lock/unlock switch (passenger’s side) connector (earth line)
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the lock/unlock switch (passenger’s side) connector (earth line) and body earth.
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
Go to Step 12.
Go to Step 11.
STEP 11. Check of open circuit in earth line between the lock/unlock switch (passenger’s side) connector and the 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 wiring harness.
STEP 12. Check of short to power supply, short to earth, or open circuit in ASRQ line between the KOS&OSS-ECU connector and the lock/unlock switch (passenger’s side) connector
Q.
Is the check result normal?
Go to Step 13.
Repair the wiring harness.
STEP 13. Keyless operation system communication test
Using M.U.T.-III, perform the antenna communication test to check that the outside transmission antenna assembly (passenger’s side) communicates normally.
- Outside transmission antenna assembly (RH)
OK: Normal values are displayed for all the items
Q.
Is the check result normal?
Go to Step 14.
Perform troubleshooting for diagnosis code No. B240A.
STEP 14. Connection check of commercial electric products
Check whether commercial electric products are connected.
Q.
Are commercial electric products connected?
Disconnect the commercial electric products as they may be interfering with communication. Then go to Step 15.
Go to Step 15.
STEP 15. Check of the troubles
Operate the lock/unlock switch (passenger’s side) and check that the doors can be locked and unlocked.
Q.
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.