Inspection Procedure M-1
Interior Light: Dome Light, Luggage Compartment LightNOTE: This troubleshooting requires use of scan tool MB991958 and SWS monitor kit MB991862. For details of how to use the SWS monitor, refer to "How to use SWS monitor." How To Use SWS Monitor
Interior Light Automatic Shut-down Function Circuit:
CIRCUIT OPERATION
The ETACS-ECU illuminates the dome light, the luggage compartment light
- Ignition switch (IG1): ON or OFF
- Key reminder switch: ON or OFF
- Front door switch: ON or OFF
- Driver's door lock actuator switch: ON or OFF
- Liftgate latch switch (vehicles with theft-alarm system) or liftgate light switch (vehicles without theft-alarm system): ON or OFF
- Trunk lid latch switch (vehicles with theft-alarm system) or trunk light switch (vehicles without theft-alarm system): ON or OFF
- Interior light loaded signal: ON
TECHNICAL DESCRIPTION (COMMENT)
If the dome light, the luggage compartment light
TROUBLESHOOTING HINTS
- Malfunction of the key reminder switch
- Malfunction of the door switch
- Malfunction of the driver's door lock actuator switch
- Malfunction of the dome light
- Malfunction of the liftgate latch switch or liftgate light switch
- Malfunction of trunk lid latch switch or trunk light switch
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface
- MB991827: MUT-III USB cable
- MB991911: MUT-III Main harness B
- MB991813: SWS monitor kit
- MB991806: SWS monitor cartridge
- MB991812: SWS monitor harness (for column-ECU)
- MB991922: Probe harness
STEP 1. Use scan tool MB991958 to select "ECU COMM Check" on the SWS monitor display.
Check the ETACS-ECU.
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 special tool MB991911 before connecting special tool MB991812. Be sure to connect special tool MB991806 after turning on special tool MB991824.
1. Connect the special tool. Refer to "How to connect SWS monitor." How to Connect SWS Monitor
2. Turn the ignition switch to the "LOCK" (OFF) position.
3. Operate scan tool MB991958 according to the procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System Select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."
4. Scan tool MB991958 should show "OK" on the "ECU COMM Check" menus for both the "ETACS ECU" menus.
Q: Is "OK" displayed on the "ETACS ECU" menu?
YES: Go to Step 2.
NO: Refer to Inspection Procedure A-3 "Communication with ETACS-ECU is impossible."
STEP 2. Check the input signal by using "DATA LIST" of the SWS monitor.
Check the input signals from the following switches:
- Ignition switch: ON or START
- Driver's or front passenger's door: open
1. Operate scan tool MB991958 according to the procedure below to display "ETACS ECU."
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "SWS MONITOR."
d. Select "DATA LIST."
e. Select "ETACS ECU."
2. Check that normal conditions are displayed on the items described in the given table.
Q: Does the scan tool display the items "IG SW (IG1)" and "FRONT DOOR SW" as normal condition?
Normal conditions are displayed for all the items: Go to Step 3.
The scan tool does not show the respective normal condition for item "IG SW (IG1)": Refer to Inspection Procedure O-2 "ETACS-ECU does not receive a signal from the ignition switch (IG1)."
The scan tool does not show the respective normal condition for item "FRONT DOOR SW": Refer to Inspection Procedure O-6 "ETACS-ECU does not receive a signal from the driver's or the front passenger's door switch."
STEP 3. Check the input signal (by using the Pulse check mode of the monitor). Check the following switches and input signals:
- Key reminder switch
- Liftgate latch switch or liftgate light switch
- Trunk lid latch switch or trunk light switch
- interior light loaded signal
1. Operate scan tool MB991958 according to the procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."
2. Check if scan tool MB991958 sounds or not.
Q: When the key reminder switch, liftgate latch switch or liftgate light switch
Normal conditions are displayed for all the items: Replace the ETACS-ECU. Check that the dome light illuminates normally.
Scan tool MB991958 does not sound when the ignition key is removed and reinserted: Refer to Inspection Procedure P-1 "ETACS-ECU does not receive a signal from the key reminder switch."
When the liftgate
When one of the interior lights is illuminated, scan tool MB991958 does not sound: Refer to Inspection Procedure P-14 "ETACS-ECU does not receive a interior light loaded signal."