Inspection Procedure 14

Inspection Procedure 14: The welcome light function does not work normally.

CAUTION:
Whenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

TECHNICAL DESCRIPTION (COMMENT)

When the welcome light function does not operate normally, the keyless entry system or the ETACS-ECU may have a problem. Or, the welcome light function may have been set to disabled using the customization function.

TROUBLESHOOTING HINTS

- Malfunction of the keyless entry system
- Malfunction of the ETACS-ECU

DIAGNOSIS

Required Special Tools:

- 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 (Vehicles with CAN communication system)

STEP 1. Using scan tool MB991958, Check the configuration function.





(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 that any one of the followings other than "Disabled" is set for "Welcome light" with a customization function.

- Small light
- Head light
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is it set to other than "Disabled"?

YES Go to Step 2.

NO Set "Welcome light" to any one other than "Disabled" with a customization function (Refer to Programming and Relearning).

STEP 2. Using scan tool MB991958, read the ETACS-ECU diagnostic trouble code

(1)Turn the ignition switch to the "ON" position.

(2)Check whether the ETACS-ECU DTC is set.

(3)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Diagnose the ETACS-ECU. (Refer to ETACS, Diagnosis Electronic Time and Alarm Control System (ETACS))
NO Go to Step 3.
STEP 3. Check the keyless entry system operation

Check that the keyless entry system operation normally.

Q. Is the check result normal?

YES Go to Step 4.
NO Troubleshoot the keyless entry system. Symptom Chart [KOS]
or Troubleshooting Symptom Chart [WCM].
STEP 4. Check the tail lights and headlights.

When the lighting switch is operated, check that the tail lights and headlights illuminate/go off normally.

Q. Is the check result normal?

YES Go to Step 5.
NO Troubleshoot the tail lights and headlights. Refer to trouble symptom chart Symptom Chart.
STEP 5. Retest the system.

Check that the welcome light function works normally.

Q. Is the check result normal?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Replace the ETACS-ECU.