Inspection Procedure 6

INSPECTION PROCEDURE 6: Ignition "LOCK (OFF)" Position-linked Door Unlock Function does not Operate. [M/T, CVT, TC-SST]

CAUTION:
Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

TECHNICAL DESCRIPTION (COMMENT)

If a door is not unlocked when the ignition switch is turned to the LOCK position, a malfunction of the CAN bus line, ignition switch or ETACS-ECU is suspected. Also, the ignition "LOCK" position-linked door unlock function may have been "Disabled" with the customization function.

TROUBLESHOOTING HINTS

- Malfunction of CAN bus line
- Malfunction of ETACS-ECU
- Malfunction of ignition switch
- Damaged wiring harness and connectors

DIAGNOSTIC PROCEDURE

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicles Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Checking central door unlocking operation

Check that the central door locking system works normally.

Q. Is the check result normal?

YES Go to Step 2.
NO Refer to trouble symptom chart Symptom Chart.
STEP 2. Check the customization function.

Check that the following other than "Disabled" is set for "Auto door unlock by ignition LOCK position" with the customization function.

- Always (LOCK pos)

Q. Is the check result normal?

YES Go to Step 3.
NO Set the function as mentioned above for "Auto door unlock by ignition LOCK position" with the customization function (Refer to Programming and Relearning).
STEP 3. Using scan tool MB991958, check CAN bus for 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. Reading and Clearing Diagnostic Trouble Codes."
(2)Turn the ignition switch to the "ON" position.
(3)Check whether the ETACS-ECU related DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Diagnose the ETACS-ECU. Refer to Sunroof System.

NO Go to Step 5.

STEP 5. Check the ignition switch.

Check that the ignition switch works normally.

Q. Is the check result normal?

YES Go to Step 6.
NO Repair the ignition switch Inspection Procedure 2).
STEP 6. Retest the system.

Check that turning the ignition switch to the "LOCK" position unlocks the doors.

Q. Is the check result normal?

YES No action is necessary and testing is complete.
NO Replace the ETACS-ECU. Check that the ignition switch to the "LOCK" (OFF) position unlocks the doors normally.