Inspection Procedure 7
Inspection Procedure 7: Driver's door lock/unlock switch does not work.
CAUTION:
Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
PROBABLE CAUSES
- Malfunction of the exterior transmitter antenna assembly
(driver's side)
- Malfunction of the lock/unlock switch (front door: LH)
- Damaged wiring harness and connectors
- Malfunction of the KOS-ECU
DIAGNOSTIC PROCEDURE
Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
STEP 1. Using scan tool MB991958, read the diagnostic trouble code.
(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958. Refer to "How to connect scan tool (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."
(2)Turn the ignition switch to the "ON" position.
(3)Check whether the KOS-ECU related DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
Q. Is the DTC set?
YES Diagnose the KOS-ECU. Refer to Keyless Operation System (KOS).
NO Go to Step 2.
STEP 2. Check KOS-ECU connector C-102 and lock/unlock switch (front door: LH) connector E-23 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q. Are KOS-ECU connector C-102 and lock/unlock switch (front door: LH) connector E-23 in good condition?
YES Go to Step 3.
NO Repair or replace the damaged component(s). Harness Connector Inspection. Check that the driver's door lock/unlock switch works normally.
STEP 3. lock/unlock switch (front door: LH) check.
(1)Remove the door outside handle base Service and Repair).
(2)Check continuity when the lock/unlock switch (front door: LH) is operated to "ON" or "OFF"
position.
Q. Is the lock/unlock switch (front: LH) normal?
YES Go to Step 4.
NO Replace the door outside handle base. Check that the driver's door lock/unlock switch works normally.
STEP 4. Check the wiring harness between KOS-ECU connector C-102 (terminal No. 21) and lock/unlock switch (front door: LH) connector E-23 (terminal No. 1), and lock/unlock switch (front door: LH) connector E-23 (terminal No. 2) and ground.
NOTE:
Also check intermediate connector C-126 and C-127 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-126 and C-127 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection Harness Connector Inspection.
Q. Are the wiring harness between KOS-ECU connector C-102 (terminal No. 21) and lock/unlock switch (front door: LH) connector E-23 (terminal No. 1), and lock/unlock switch (front door:
LH) connector E-23 (terminal No. 2) and ground in good condition?
YES Go to Step 5.
NO The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Check that the driver's door lock/unlock switch works normally.
STEP 5. KOS communication test
Using scan tool (M.U.T-III), perform the antenna communication test to check that the exterior transmitter antenna (driver's side) communicates normally (Refer to Testing and Inspection).
Q. Is the check result normal?
YES Go to Step 6.
NO Perform troubleshooting for the diagnostic trouble code No. B240A (Refer to Keyless Operation System (KOS)).
STEP 6. Check of the troubles.
Operate the lock/unlock switch (front door: LH) and check that the door and liftgate can be locked.
Q. Is the check result normal?
YES Intermittent malfunction is suspected How to Cope With Intermittent Malfunctions).
NO Replace KOS-ECU and register the ID codes (Refer to ID Codes Registration Procedure).