Page 121 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-121
If the passenger's door or driver's door are locked
while the passenger's door is open and when the key
is still in the ignition key cylinder, approximately 0.3
second later the ETACS-ECU activates the unlock
relay output for 0.25 second to prevent the door from
being locked with the key inside the vehicle.In addition, if locking the door was not prevented, a
re-try current is sent (an unlock relay output ON is
sent for 0.25 second up to 5 times including the first
attempt).
NOTE: The dotted line indicates that the system is
trying to turn on the unlock relay if the door cannot be
unlocked.
Page 122 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-122
INSPECTION PROCEDURE C-1: Central Door Locking System: The Central Door Locking System
does not Work at all.
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 ETACS-ECU controls the central door lock
system, locking or unlocking all the doors by acti-
vating the central door lock relay (built into the
ETACS-ECU). The ETACS-ECU uses inputs from
the following components:
Front door lock actuator
Front door lock key cylinder switch
Door lock switch, which is incorporated in the
power window main switch or front power win-
dow sub switch
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The ETACS-ECU may be defective
Page 123 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-123
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
MB991813: SWS Monitor Kit
MB991806: SWS Monitor Cartridge
MB991812: SWS Monitor Harness (For Column-ECU)
MB991822: Test Probe Harness
STEP 1. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the ETACS-ECU.
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958. Connect special tool MB991910 before con-
necting 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 P.54B-13."
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Operate diagnostic 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) MUT-III 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 P.54B-74."
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 125 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-125
STEP 4. Check the wiring harness between ETACS-ECU
connector C-219 (terminal 2) and fusible link (1).
NOTE: Also check junction block connector C-216 and inter-
mediate connector C-31 for loose, corroded, or damaged termi-
nals, or terminals pushed back in the connector. If junction
block connector C-216 or intermediate connector C-31 is dam-
aged, 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 2) and fusible link (1) in good condition?
YES : No action is necessary and testing is complete.
NO : The wiring harness may be damaged or the connector
may have loose, corroded or damaged terminals, or
terminals pushed back in the connector. Repair the
wiring harness as necessary. Verify that the central
door locking system works normally.
Page 126 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-126
STEP 5. Check ETACS-ECU connectors C-217 and front
door lock actuator (RH) connector E-05 for loose, corroded
or damaged terminals, or terminals pushed back in the
connector.
Q: Are ETACS-ECU connectors C-217 and front door lock
actuator (RH) connector E-05 in good condition?
YES : Go to Step 6.
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 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 6. Check the wiring harness between ETACS-ECU
connector C-217 (terminal 22) and front door lock actuator
(RH) connector E-05 (terminal 6).
Page 127 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-127
NOTE: Also check intermediate connector C-12 for loose, cor-
roded, or damaged terminals, or terminals pushed back in the
connector. If intermediate connector C-12 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-217 (terminal 22) and front door lock actuator (RH)
connector E-05 (terminal 6) in good condition?
YES : Go to Step 7.
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.
STEP 7. Check the wiring harness between ETACS-ECU
connector C-219 (terminal 12) and front door lock actuator
(RH) connector E-05 (terminal 4).
Page 128 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-128
NOTE: Also check intermediate connector C-12 and junction
block connector C-211 for loose, corroded, or damaged termi-
nals, or terminals pushed back in the connector. If intermediate
connector C-12 or junction block connector C-211 are dam-
aged, 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 12) and front door lock actuator (RH)
connector E-05 (terminal 4) in good condition?
YES : Replace the ETACS-ECU. Verify that all the doors
can be locked and unlocked normally.
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 or replace the damaged component(s). Verify
that the central door locking system works normally.