Inspection Procedure 4

Inspection Procedure 4: The Interior Light Auto-Cut Function Does Not Operate Correctly.

TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU operates the interior light auto-cut function in accordance with the input signals below.
- Ignition switch (ACC)
- Ignition switch (IG1)
- Door switches

If this function does not work normally, these input signal circuit(s) or the ETACS-ECU may have a problem. Also, "Interior light auto cut timer" may be set to "Disable" through customization.

TROUBLESHOOTING HINTS
- Malfunction of door switch
- Malfunction of the dome light
- Malfunction of the ETACS-ECU
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

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. Use the ETACS-ECU customize function to check to see which of the followings other than "Disable" the "Interior light auto cut timer" is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the check result normal?

YES : Go to Step 2.

NO : Use the ETACS-ECU configuration function to set the "Interior light auto cut timer" to other than "Disable". Programming and Relearning

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

Check if DTC is set to the ETACS-ECU.

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 interior light auto-cut function.
- Turn the ignition switch to the "LOCK" (OFF) position.
- Open each door.







Q: Does scan tool MB991958 display the items "IG voltage", "ACC switch", "Dr door ajar switch", "As door ajar switch", "RR door ajar switch", and "RL door ajar switch" as normal condition?

YES : (Normal conditions are displayed for all items.) Go to Step 4.

NO : (Normal condition is not displayed.) Troubleshoot the ETACS-ECU. Refer to ETACS, Diagnosis, Input signal chart. Trouble Symptom Chart For Input Signal

STEP 4. Retest the system.

Check that the interior light automatic shutdown function works normally.

Q: Is the check result normal?

YES : The trouble can be an intermittent malfunction.

NO : Replace the ETACS-ECU.