Inspection Procedure 6

INSPECTION PROCEDURE 6: Ignition "LOCK (OFF)" Position-linked Door Unlock Function does not Operate. [M/T, 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 other than "Disabled" for "Auto door unlock by ignition LOCK position" with the customization function.

STEP 3. Using scan tool MB991958, check CAN bus for diagnostic trouble code.

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.







1. Connect scan tool MB991958. Refer to keyless operation system (KOS), "How to connect scan tool (M.U.T.-III)"
2. Turn the ignition switch to the "ON" position.
3. Check whether CAN bus lines related DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES: Repair the CAN bus line (Refer to Controller area network, CAN bus diagnostics table).

NO: Go to Step 4.

STEP 4. Using scan tool MB991958, read the diagnostic trouble code.

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.







1. Connect scan tool MB991958. Refer to keyless operation system (KOS), "How to connect scan tool (M.U.T.-III)".
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.

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 (Refer to chassis electrical - Ignition Switch Troubleshooting/Inspection Procedure 2 - Defective power supply system of the ignition switch).

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.