SYMPTOM PROCEDURES
TSB Revision
SIMPLIFIED WIRING SYSTEM (SWS)
54B-460
INSPECTION PROCEDURE K-7: Interior Light: The seat belt warning light do 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 mon-
itor, refer to "How to use SWS monitor
P.54B-15
."
.
CIRCUIT OPERATION
The combination meter and the ETACS-ECU illumi-
nates 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 termi-
nals pushed back in the connector
• The combination meter may be defective
• The ETACS-ECU may be defective
DIAGNOSIS
Required Special Tools:
• MB991223: Harness Set
• MB991958: Scan Tool (MUT-III Sub Assembly)
• MB991824: Vehicle Communication Interface (V.C.I.)
• MB991827: MUT-III USB Cable
• MB991910: MUT-III Main Harness A
• MB991813: SWS Monitor Kit
• MB991806: SWS Monitor Cartridge
• MB991812: SWS Monitor Harness (For Column-ECU)
• MB991822: Probe Harness
·IGNITION SWITCH (IG1)
·SEAT BELT SWITCH
·VEHICLES SPEED
SIGNAL
COMBINATION
METER
ETACS-ECU
INPUT SIGNAL
CAN COMMUNICATION LINE
(CAN_H_LINE)
CAN COMMUNICATION LINE
(CAN_L_LINE)
Seat Belt Warning Light Circuit