Inspection Procedure L-1

INSPECTION PROCEDURE L-1: Interior Light: The dome lights do not illuminate and go out normally.

NOTE:
This troubleshooting procedure requires the use of scan tool MB991958 and SWS monitor kit MB991813. For details on how to use the SWS monitor, refer to "How to use SWS monitor How to Use SWS Monitor."






CIRCUIT OPERATION

The ETACS-ECU operates the dome lights according to the following signals:

- Ignition switch (IG1): ON or OFF
- Key reminder switch: ON or OFF
- Door switches: ON or OFF
- Driver's door lock actuator switch: ON or OFF
- Interior light loaded signal: ON

TECHNICAL DESCRIPTION (COMMENT)

If the dome lights does not illuminate normally, a burned-out dome light bulb, the input circuits from the switches described in "CIRCUIT OPERATION", the power supply line to the switches or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS

- Trouble in input signal system
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The ETACS-ECU may be defective

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
- MB991813: SWS Monitor Kit
- MB991806: SWS Monitor Cartridge
- MB991812: SWS Monitor Harness (For Column-ECU)
- MB991822: Probe Harness

STEP 1. Use scan tool MB991958 to select "ECU COMM Check" on the SWS monitor display.

Check the ETACS-ECU.









(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 special tool MB991910 before connecting special tool MB991812. Be sure to connect special tool MB991806 after turning on special tool MB991824.

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."

.....Select "Interactive Diagnosis."

.....Select "System select."

.....Select "SWS."

.....Select "SWS MONITOR."

.....Select "ECU COMM Check."
(4)Scan tool MB991958 should show "OK" on the "ECU COMM Check" menu for the "ETACS ECU" menu.

Q. Is "OK" displayed for the "ETACS ECU" menu?

YES Go to Step 2.

NO Refer to Inspection Procedure A-3 "Communication with the ETACS-ECU is not possible Inspection Procedure A-3."

STEP 2. Check the input signal by using "DATA LIST" menu of the SWS monitor.









Check the input signals from the following switches:

- Ignition switch: ON or START
- Driver's or passenger's door: open
(1)Operate scan tool MB991958 according to the procedure below to display "ETACS ECU."

.....Select "Interactive Diagnosis."

.....Select "System select."

.....Select "SWS."

.....Select "SWS MONITOR."

.....Select "Data List."

.....Select "ETACS ECU."
(2)Check that normal conditions are displayed for the items described in the table below.





Q. Does the scan tool MB991958 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.

Normal condition is not displayed for "IG SW (IG1)" : Refer to Inspection Procedure M-2 "ETACS-ECU does not receive any signal from the ignition switch (IG1) Inspection Procedure M-2."

Normal condition is not displayed for "FRONT DOOR SW" : Refer to Inspection Procedure M-5 "ETACS-ECU does not receive any signal from the door switches Inspection Procedure M-5."

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
- Interior light loaded signal
(1)Operate scan tool MB991958 according to the procedure below to display "Pulse check."

.....Select "Interactive Diagnosis."

.....Select "System select."

.....Select "SWS."

.....Select "Pulse Checking."
(2)Check if scan tool MB991958 sounds or not.





Q. When the key reminder switch, any door switch or interior light is operated, does scan tool MB991958 sound?

Buzzer of scan tool MB991958 sounds normally. : Replace the ETACS-ECU. When the ETACS-ECU is replaced, register the encrypted code. Encrypted Code Registration Criteria Table. Verify that the dome light illuminates normally.

Scan tool MB991958 does not sound when the ignition key is removed and reinserted : Refer to Inspection Procedure N-1 "ETACS-ECU does not receive any signal from the key reminder switch Inspection Procedure N-1."

When one of the interior lights is illuminated, scan tool MB991958 does not sound : Refer to Inspection Procedure N-8 "ETACS-ECU does not receive any interior light loaded signal Inspection Procedure N-8."