Inspection Procedure 15

Inspection Procedure 15: The Coming Home 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 coming home light function does not operate normally, the keyless entry system or the ETACS-ECU may have a problem. Or, the coming home 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.

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 "How to connect scan tool (M.U.T.-III)." How to Connect the Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "ON" position.
3. Check that any one of the followings other than "Disabled" is set for "Coming home light" with a customization function.
- 15 sec
- 30 sec
- 60 sec
- 180 sec

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 "Coming home light" to any one other than "Disabled" with a customization function. 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) Diagnostic Trouble Code Descriptions

NO : Go to Step 3.

STEP 3. Using scan tool MB991958, check data list

Use the ETACS-ECU data list to check the signals related to the front dome light.
- Turn the ignition switch to the LOCK (OFF) position.







OK: Normal condition is displayed.

Q: Is the check result normal?

YES : Go to Step 4.

NO : Troubleshoot the ETACS-ECU. Refer to Inspection Procedure 2 "The ignition switch (IG1) signal is not received". Inspection Procedure 2

STEP 4. Check the headlights.

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

Q: Is the check result normal?

YES : Go to Step 5.

NO : Troubleshoot the headlights. Refer to trouble symptom chart. Trouble Symptom Chart

STEP 5. Retest the system.

Check that the coming home light function works normally.

Q: Is the check result normal?

YES : The trouble can be an intermittent malfunction.

NO : Replace the ETACS-ECU.