Page 441 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-441
STEP 1. Check the input signal (by using the pulse check
mode of the monitor).
Check the input signals from the all door switches.
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect the diagnostic tool MB991958. Refer to "How to
connect SWS monitor P.54B-13."
(2) Operate diagnostic tool MB991958 according to the
procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."
(3) Check that diagnostic tool MB991958 sounds.
Q: When the front and rear doors are opened/closed, does
the diagnostic tool MB991958 sound?
When the front doors are opened and closed, diagnostic
tool MB991958 does not sound. : Refer to Inspection
Procedure M-4 "ETACS-ECU does not receive any
signal from the front door switches P.54B-413."
When the rear door (LH) is opened and closed,
diagnostic tool MB991958 does not sound. : Go to Step
2.
When the rear door (RH) is opened and closed,
diagnostic tool MB991958 does not sound. : Go to Step
7.
STEP 2. Check rear door switch (LH) connector D-16 for
loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is rear door switch (LH) connector D-16 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. If the functions described in "CIRCUIT
OPERATION" work normally, the input signal from the
rear door switch (LH) should be normal.
Page 442 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-442
STEP 3. Check the rear door switch (LH).
Remove the rear door switch (LH). Refer to GROUP 42, Door,
Door Assembly P.42-37. Then check continuity between the
switch terminals and the body ground.
Q: Is the rear door switch (LH) in good condition?
YES : Go to Step 4.
NO : Replace the rear door switch (LH). If the functions
described in "CIRCUIT OPERATION" work normally,
the input signal from the rear door switch (LH) should
be normal.
STEP 4. Measure resistance at the lower metal part of the
rear door switch (LH) in order to check the ground circuit
to the rear door switch (LH).
NOTE: Check that the rear door switch (LH) is grounded to the
vehicle body via its mounting screw.
Remove the cap, and measure the resistance value between
the lower metal part and ground.
The resistance should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
YES : Go to Step 5.
NO : Check the installation of the switch, and repair if
necessary. If the functions described in "CIRCUIT
OPERATION" work normally, the input signal from the
rear door switch (LH) should be normal.
STEP 5. 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 6.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. If the functions described in "CIRCUIT
OPERATION" work normally, the input signal from the
rear door switch (LH) should be normal. SWITCH
POSITIONTESTER
CONNECTIONSPECIFIED
CONDITION
Released (ON) 1
body ground Less than 2 ohms
Pressed (OFF) 1
body ground Open circuit
Page 443 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-443
STEP 6. Check the wiring harness between rear door
switch (LH) connector D-16 (terminal 1) and ETACS-ECU
connector C-219 (terminal 7).
NOTE: Also check junction block connector C-204 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-204 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 rear door switch (LH)
connector D-16 (terminal 1) and ETACS-ECU connector
C-219 (terminal 7) in good condition?
YES : Replace the ETACS-ECU. If the functions described
in "CIRCUIT OPERATION" work normally, the input
signal from the rear door switch (LH) should be
normal.
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. If the
functions described in "CIRCUIT OPERATION" work
normally, the input signal from the rear door switch
(LH) should be normal.
Page 444 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-444
STEP 7. Check rear door switch (RH) connector D-06 for
loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is rear door switch (RH) connector D-06 in good
condition?
YES : Go to Step 8.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. If the functions described in "CIRCUIT
OPERATION" work normally, the input signal from the
rear door switch (RH) should be normal.
STEP 8. Check the rear door switch (RH).
Remove the rear door switch (RH). Refer to GROUP 42, Door,
Door Assembly P.42-37. Then check continuity between the
switch terminals and the body ground.
Q: Is the rear door switch (RH) in good condition?
YES : Go to Step 9.
NO : Replace the rear door switch (RH). If the functions
described in "CIRCUIT OPERATION" work normally,
the input signal from the rear door switch (RH) should
be normal.
STEP 9. Measure resistance at the lower metal part of the
rear door switch (RH) in order to check the ground circuit
to the rear door switch (RH).
NOTE: Check that the rear door switch (RH) is grounded to the
vehicle body via its mounting screw.
Remove the cap, and measure the resistance value between
the lower metal part and ground.
The resistance should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
YES : Go to Step 10.
NO : Check the installation of the switch, and repair if
necessary. If the functions described in "CIRCUIT
OPERATION" work normally, the input signal from the
rear door switch (RH) should be normal.
SWITCH
POSITIONTESTER
CONNECTIONSPECIFIED
CONDITION
Released (ON) 1
body ground Less than 2 ohms
Pressed (OFF) 1
body ground Open circuit
Page 445 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-445
STEP 10. Check ETACS-ECU connector C-217 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is ETACS-ECU connector C-217 in good condition?
YES : Go to Step 11.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. If the functions described in "CIRCUIT
OPERATION" work normally, the input signal from the
rear door switch (RH) should be normal.
STEP 11. Check the wiring harness between rear door
switch (RH) connector D-06 (terminal 1) and ETACS-ECU
connector C-217 (terminal 35).
Q: Is the wiring harness between rear door switch (RH)
connector D-06 (terminal 1) and ETACS-ECU connector
C-217 (terminal 35) in good condition?
YES : Replace the ETACS-ECU. If the functions described
in "CIRCUIT OPERATION" work normally, the input
signal from the rear door switch (RH) should be
normal.
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. If the
functions described in "CIRCUIT OPERATION" work
normally, the input signal from the rear door switch
(RH) should be normal.
Page 446 of 1500
INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-446
INSPECTION PROCEDURE N-4: ETACS-ECU does not receive any signal from the door lock key
cylinder switch.
.
CIRCUIT OPERATION
The ETACS-ECU operates the central door locking
system according to signal from the door lock key
cylinder switch.
.
TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the systems, which are
described in "CIRCUIT OPERATION", do not work
normally.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The door lock key cylinder switch may be defec-
tive
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 447 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-447
DIAGNOSIS
Required Special Tool:
MB991223: Harness Set
STEP 1. Check door lock key cylinder switch connector
E-14 for loose, corroded or damaged terminals, or
terminals pushed back in the connector.
Q: Is door lock key cylinder switch connector E-14 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. If the systems described in "CIRCUIT
OPERATION" work normally, the input signal from the
door lock key cylinder switch should be normal.
STEP 2. Check the door lock key cylinder switch.
Disconnect door lock key cylinder switch connector E-14. Then
check continuity between the switch terminals.
Q: Is the door lock key cylinder switch in good condition?
YES : Go to Step 3.
NO : Replace the door lock key cylinder switch. If the
systems described in "CIRCUIT OPERATION" work
normally, the input signal from the door lock key
cylinder switch should be normal.
SWITCH
POSITIONTESTER
CONNECTIONSPECIFIED
CONDITION
LOCK 2
3 Less than 2 ohms
Neutral (OFF) 1
2, 2 3 Open circuit
UNLOCK 1
2 Less than 2 ohms
Page 448 of 1500
INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-448
STEP 3. Check the ground circuit to the door lock key
cylinder switch. Measure the resistance at door lock key
cylinder switch connector E-14.
(1) Disconnect door lock key cylinder switch connector E-14
and measure the resistance available at the wiring harness
side of the connector.
(2) Measure the resistance value between terminal 2 and
ground.
The resistance should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
YES : Go to Step 5.
NO : Go to Step 4.
STEP 4. Check the wiring harness between door lock key
cylinder switch connector E-14 (terminal 2) and ground.