Inspection Procedure L-8

INSPECTION PROCEDURE L-8: Interior Light: The seat belt warning light does not illuminate or 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 combination meter and the ETACS-ECU illuminates and flashes the seat belt warning light by using the signal from the seat belt switch, the ignition switch (IG1) and the vehicle speed signal.

TECHNICAL DESCRIPTION (COMMENT)

If the seat belt warning light does not illuminate or flash correctly, connector(s), wiring harness in the CAN bus lines, the door switches, the ETACS-ECU, or the combination meter 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 combination meter may be defective
- 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. Using scan tool MB991958, diagnose the CAN bus line.





(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 SWS monitor How to Connect SWS Monitor."
(2)Turn the ignition switch to the "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the CAN bus line found to be normal?

YES Go to Step 2.

NO Repair the CAN bus line CAN Bus Diagnostics Chart).

STEP 2. Using scan tool MB991958, read the combination meter diagnostic trouble code.





(1)Check whether the combination meter-related DTC is set.
(2)Turn the ignition switch to the "ON" position.
(3)Check whether the combination meter-related DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Diagnose the combination meter. Refer to Combination Meter.

NO Go to Step 3.

STEP 3. Use scan tool MB991958 to select "ECU COMM Check" on the SWS monitor display.

Check the ETACS-ECU.









(1)
CAUTION:
Connect special tool MB991910 before connecting special tool MB991812. Be sure to connect special tool MB991806 after turning on special tool MB991824.

Connect the SWS monitor. 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 4.

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

STEP 4. Check the input signal by using "DATA LIST" menu of the SWS monitor.









Check the input signals from the following switches:

- Ignition switch: ON
(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. Is the scan tool MB991958 display the items "IG SW (IG1)" normal condition?

YES Go to Step 5.

NO Refer to Inspection Procedure M-2 "ETACS-ECU does not receive any signal from the ignition switch (IG1) Inspection Procedure M-2."

STEP 5. Replace the combination meter.

(1)Replace the combination meter.

(2)Check that the seat belt warning light illuminates normally.

Q. Is the seat belt warning light in good condition?

YES No action is necessary and testing is complete.
NO Replace the ETACS-ECU. When the ETACS-ECU is replaced, register the encrypted code. Immobilizer System. Verify that the seat belt warning light illuminates normally.