Inspection Procedure 5

INSPECTION PROCEDURE 5: Selector "P" Position-linked Door Unlock Function does not Operate Normally. [TC-SST]

CAUTION:
Whenever the ECU is replaced, ensure that the input and output signal circuits are normal.





OPERATION

ETACS-ECU determines whether the shift position is at "P" or not according to the shift position signal which is sent by shift lever.

TECHNICAL DESCRIPTION (COMMENT)

If the doors are not unlocked when the selector lever is shifted to the P position, a malfunction of the shift position signal input circuit(s) or ETACS-ECU is suspected. Also, the selector "P" position-linked door unlock function may have been "Disabled" with the customization function.

TROUBLESHOOTING HINTS

- Malfunction of shift lever
- Malfunction of ETACS-ECU
- Damaged wiring harness and connectors

DIAGNOSTIC PROCEDURE

Required Special Tools:

- MB992006: Extra fine probe
- MB991223: Harness set
- 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 locking system operation

Check that the central door locking system works normally.

Q. Is the check result normal?

YES Go to Step 2.
NO Refer to Inspection procedure 1 "Central door locking system does not work at all Inspection Procedure 1."
STEP 2. Check the customize function.

Check that the followings other than "Disable" is set for "Auto door unlock by P position"
with the customization function.

- Always (P pos)

Q. Is the check result normal?

YES Go to Step 3.
NO Set the function as mentioned above for "Auto door unlock by P position" with the customization function (Refer to Programming and Relearning).
STEP 3. Using scan tool MB991958, read CAN bus 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 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 CAN Bus Diagnostics Chart).

NO Go to Step 4.

STEP 4. 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 shift lever related DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Diagnose the shift lever. Twin Clutch-Sportronic Shift Transmission (TC-SST).

NO Go to Step 5.

STEP 5. Retest the system.

Check that shifting the selector lever to the P 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 selector lever to the P position unlocks the doors normally.