Inspection Procedure 6: Driver’s door lock/unlock switch does not work.


caution Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

PROBABLE CAUSES



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 .

Go to Step 2.

STEP 2. Lock/unlock switch (driver’s side) check


Check that the lock/unlock switch (driver’s side) is normal (Refer to GROUP 42A - Door Latch Assembly Inspection ).

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)


(1)Disconnect the connector, and measure at the wiring harness side.
(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)

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?

Go to Step 6.

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 (Refer to ).

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 (Refer to ).

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 (Refer to ).