Page 76 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-76
STEP 3. Check the wiring harness between ETACS-ECU
connector C-219 (terminal 20) and the battery.
NOTE: Also check junction block connector C-214 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-214 is damaged,
repair or replace the damaged component(s) as described in
GROUP 00E, Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between ETACS-ECU connector
C-219 (terminal 20) and the battery in good condition?
YES : No action is necessary and testing is complete.
NO : The wiring harness may be damaged or the
connector(s) may have loose, corroded or damaged
terminals, or terminals pushed back in the connector.
Repair the wiring harness as necessary. The system
should communicate with the ETACS-ECU normally.
STEP 4. Check the ground circuit to the ETACS-ECU.
Measure the resistance at ETACS-ECU connector C-219.
(1) Disconnect ETACS-ECU connector C-219 and measure the
resistance available at the junction block side of the
connector.
(2) Measure the resistance value between terminal 3 and
ground.
The resistance should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
YES : Go to Step 6.
NO : Go to Step 5.
Page 80 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-80
INSPECTION PROCEDURE A-4: Communication with the Front-ECU is not Possible.
NOTE: This troubleshooting procedure requires the
use of diagnostic tool MB991958 and SWS monitor
kit MB991813. For details on how to use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The power supply to the front-ECU is provided by
the battery and the ignition switch (IG2).
If the power supply system from the battery is
defective, the system operates by the power sup-
ply from the ignition switch (IG2).
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
.
TECHNICAL DESCRIPTION (COMMENT)
It is suspected that the power supply circuit to the
front-ECU is defective, or the wiring harness
between the SWS monitor kit and the front-ECU or
their connector(s) is damaged. If the battery power
supply circuit to the ECU (terminal 5 of the
front-ECU) is damaged, also check the power supply
circuit from the ignition switch (IG2) (terminal 22 of
the front-ECU), and repair if necessary.
.
TROUBLESHOOTING HINTS
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The front-ECU may be defective
The ETACS-ECU may be defective
Page 83 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-83
STEP 2. Check front-ECU connector A-11X for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is front-ECU connector A-11X in good condition?
YES : Go to Step 3.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. The system should communicate with the
front-ECU normally.
STEP 3. Check the battery power supply circuit to the
front-ECU. Measure the voltage at front-ECU connector
A-11X.
(1) Disconnect front-ECU connector A-11X and measure the
voltage available at the relay box side of the connector.
(2) Measure the voltage between terminal 5 and ground.
The voltage should measure approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery
positive voltage)?
YES : Go to Step 5.
NO : Go to Step 4.
Page 84 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-84
STEP 4. Check the wiring harness between front-ECU
connector A-11X (terminal 5) and the battery.
Q: Is the wiring harness between front-ECU connector
A-11X (terminal 5) and the battery in good condition?
YES : No action is necessary and testing is complete.
NO : The wiring harness may be damaged or the
connector(s) may have loose, corroded or damaged
terminals, or terminals pushed back in the connector.
Repair the wiring harness as necessary. The system
should communicate with the front-ECU normally.
STEP 5. Check front-ECU connector A-12X for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is front-ECU connector A-12X in good condition?
YES : Go to Step 6.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. The system should communicate with the
front-ECU normally.
STEP 6. Check the ground circuit to the front-ECU.
Measure the resistance at front-ECU connector A-12X.
(1) Disconnect front-ECU connector A-12X and measure the
resistance available at the relay box side of the connector.
(2) Measure the resistance value between terminal 21 and
ground.
The resistance should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
YES : Go to Step 8.
NO : Go to Step 7.
Page 88 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-88
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
MB991958: DIAGNOSTIC TOOL (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
STEP 1. Check sunroof motor assembly connector D-04
for loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is sunroof motor assembly connector D-04 in good
condition?
YES : Go to Step 2.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. The system should communicate with the
sunroof-ECU normally.
STEP 2. Check the fusible link (5) line of power supply
circuit to the sunroof motor assembly. Measure the voltage
at sunroof motor assembly connector D-04.
(1) Disconnect sunroof motor assembly connector D-04 and
measure the voltage available at the wiring harness side of
the connector.
(2) Measure the voltage between terminal 1 and ground.
The voltage should measure approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery
positive voltage)?
YES : Go to Step 4.
NO : Go to Step 3.
Page 91 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-91
STEP 4. Check the ignition switch (IG2) circuit to the
sunroof motor assembly. Measure the voltage at sunroof
motor assembly connector D-04.
(1) Disconnect sunroof motor assembly connector D-04 and
measure the voltage available at the wiring harness side of
the connector.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 2 and ground.
The voltage should measure approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery
positive voltage)?
YES : Go to Step 6.
NO : Go to Step 5.
STEP 5. Check the wiring harness between sunroof motor
assembly connector D-04 (terminal 2) and ignition switch
(IG2).
Page 124 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-124
STEP 2. Check ETACS-ECU connector C-219 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is ETACS-ECU connector C-219 in good condition?
YES : Go to Step 3.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the central door locking system
works normally.
STEP 3. Check the battery power supply circuit to the
ETACS-ECU. Measure the voltage at ETACS-ECU
connector C-219.
(1) Disconnect ETACS-ECU connector C-219 and measure the
voltage available at the junction block side of the connector.
(2) Measure the voltage between terminal 2 and ground.
The voltage should measure approximately 12 volts
(battery positive voltage)
Q: Is the measured voltage approximately 12 volts (battery
positive voltage)?
YES : Go to Step 5.
NO : Go to Step 4.
Page 131 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-131
STEP 3. Check the front door lock actuator (RH).
Remove the front door lock actuator (RH). The illustration
shows when the door lock actuator is viewed from inside the
door. Refer to GROUP 42
Door Handle and Latch P.42-46.
Q: Does the front door lock actuator (RH) work normally?
YES : Go to Step 4.
NO : Replace the front door lock actuator (RH). Verify that
all the doors can be locked and unlocked normally.
STEP 4. Check ETACS-ECU connectors C-217 and C-219
for loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Are ETACS-ECU connectors C-217 and C-219 in good
condition?
YES : Go to Step 5.
NO : Repair or check the connector. Refer to GROUP 00E,
Harness Connector Inspection P.00E-2. Verify that all
the doors can be locked and unlocked normally. LEVER
POSITIONBATTERY
CONNECTIONLEVER
OPERATION
At the "LOCK"
position
Connect terminal 4
to the negative
battery terminal
Connect terminal 6
to the positive
battery terminalThe lever moves
from the "LOCK"
position to the
"UNLOCK"
position.
At the
"UNLOCK"
position
Connect terminal 6
to the negative
battery terminal
Connect terminal 4
to the positive
battery terminalThe lever moves
from the "UNLOCK"
position to the
"LOCK" position.