SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-118
STEP 4. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
Check the input signals from the following switches:
Ignition switch: ON
Driver’s door: Open
All door: Closed
(1) Operate diagnostic tool MB991958 according to the
procedure below to display "OTHER ALARM"
a. Select "Interactive Diagnosis."
b. Select "System Select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "BUZZER."
g. Select "OTHER ALARM"
(2) Check that normal conditions are displayed for the items
described in the table below.
NOTE: The diagnostic tool MB991958 display changes
when the driver's or the front passenger's door is opened. If
any of the doors is open, the system cannot be checked
correctly.
Q: Does diagnostic tool MB991958 display the items "IG
SW (IG1)" and "BUZZER" as normal condition?
Normal conditions are displayed for all the items :
Replace the ETACS-ECU. Check that the turn-signal
lamp buzzer function works normally.
Normal condition is not displayed for "IG SW (IG1)" :
Refer to Inspection Procedure M-2 "ETACS-ECU
does not receive any signal from the ignition switch
(IG1) P.54B-408."
Normal condition is not displayed for "BUZZER" :
Replace the ETACS-ECU. Check that the turn-signal
lamp buzzer function works normally.
CENTRAL DOOR LOCKING SYSTEM
GENERAL DESCRIPTION CONCERNING CENTRAL DOOR LOCKING SYSTEMM1549021100271
The following ECUs affect the functions and control
of the central door locking system.ITEM NO. ITEM NAME NORMAL
CONDITION
ITEM 30 IG SW (IG1) ON
ITEM 43 BUZZER ON
FUNCTIONCONTROL ECU
Central door locking system ETACS-ECU
Forgotten key prevention function ETACS-ECU
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-119
CENTRAL DOOR LOCKING SYSTEM
.
DOOR UNLOCKING BY OPERATING THE
DRIVER’S DOOR LOCK KEY CYLINDER
When the ignition key is inserted in the driver’s door lock key
cylinder and turned anti-clockwise to unlock the driver’s door,
the ETACS-ECU operates its door unlock relay and passes a
current through the door lock actuator of the driver’s door for
0.25 seconds to unlock only the driver’s door.
When the ignition key is turned anti-clockwise again, the
ETACS-ECU operates its door unlock relay and passes a cur-
rent through the door lock actuators of all doors for 0.25 sec-
onds and to unlock all doors.
NOTE: Vehicles with a multi center display (middle grade type)
can be customized so that a single unlock operation will unlock
all doors. Refer to P.54B-486.
.
DOOR LOCKING OR UNLOCKING BY
OPERATING THE DRIVER’S OR FRONT
PASSENGER’S DOOR LOCK SWITCH
When the door is locked by the driver’s or front passenger’s
door lock switch, the ETACS-ECU operates its door lock relay
and passes a current through the door lock actuators of all
doors for 0.25 seconds to lock all doors.
When the door is unlocked by the driver’s or front passenger's
door lock switch, the ETACS-ECU operates its door unlock
relay and passes a current through the door lock actuators of
all doors for 0.25 seconds to unlock all doors.
When the door is locked and unlocked by driver’s or front pas-
senger's door lock switch consecutively, the ETACS-ECU oper-
ates its door lock relay and passes a current through the door
lock actuators of all doors for 0.25 seconds to lock all doors.
Then, the ETACS-ECU operates its door unlock relay and
passes a current through the door lock actuators of all doors for
0.25 seconds to unlock all doors. Due to this, there may be a
time lag between the driver’s or front passenger's door lock
switch actuation and the time when all doors are unlocked.
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."
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-142
INSPECTION PROCEDURE C-3: Central Door Locking System: All the Doors do not Lock or Unlock
with just the Door Lock Switch Operation.
.
TECHNICAL DESCRIPTION (COMMENT)
The door lock switch (incorporated in the power win-
dow main switch and front power window sub switch)
or the ETACS-ECU may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
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 ETACS-ECU may be defective
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
Check the input signal (by using the pulse check mode of
the monitor).
Check the input signals from the door lock switch (incorporated
in the power window main switch and front power window sub
switch):
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 special tool. Refer to "How to connect SWS
monitor P.54B-13."
(2) When the driver's or the front passenger's door lock switch
is moved from "LOCK" to "UNLOCK" and vice versa, check
if diagnostic tool MB991958 sounds or not.
(3) 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."
Q: Does diagnostic tool MB991958 sound when the driver's
or the front passenger's door lock switch is moved from
"LOCK" to "UNLOCK" and vice versa?
YES : Replace the ETACS-ECU. Check that all the doors
should be locked and unlocked by the door lock
switch.
NO : Refer to Inspection Procedure N-6 "ETACS-ECU
does not receive any signal from the door lock switch
(incorporated in the power window main switch and
front power window sub switch) P.54B-460."
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-143
INSPECTION PROCEDURE C-4: Central Door Locking System: All the Doors do not Lock or Unlock
with just the Door Lock Key Cylinder Key Operation.
.
TECHNICAL DESCRIPTION (COMMENT)
The door lock key cylinder switch or the ETACS-ECU
may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
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 ETACS-ECU may be defective
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
Check the input signal (by using the pulse check mode of
the monitor).
Check the input signals from the door lock key cylinder switch.
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 special tool. Refer to "How to connect SWS
monitor P.54B-13."
(2) When the doors are locked and unlocked by using the
driver's door lock key cylinder, check that diagnostic tool
MB991958 sounds.
(3) 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."
Q: When the doors are locked and unlocked by using the
driver's door lock key cylinder, does diagnostic tool
MB991958 sound?
YES : Replace the ETACS-ECU. Check that all the doors
should be locked and unlocked by using driver door
lock key cylinder switch.
NO : Refer to Inspection Procedure N-4 "ETACS-ECU
does not receive any signal from the door lock key
cylinder switch P.54B-446."
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-145
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) diagnostic 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 2.
NO : Refer to Inspection Procedure A-3 "Communication
with the ETACS-ECU is not possible P.54B-74."
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-146
STEP 2. Check the input signal by using "DATA LIST"
menu of the SWS monitor.
Turn the ignition switch to the "ON" position before checking
input signals from the ignition switch (IG1).
(1) Operate the diagnostic tool MB991958 according to the
procedure below to display "ETACS ECU."
a. Select "Interactive Diagnosis."
b. Select "System Select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Data List."
f. Select "ETACS ECU."
(2) Check that normal conditions are displayed for the items
described in the table below.
Q: Does diagnostic tool MB991958 display "FRONT DOOR
SW" as normal condition?
YES : Go to Step 3.
NO : Refer to Inspection Procedure M-4 "ETACS-ECU
does not receive any signal from the front door
switches P.54B-413." ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 32 FRONT DOOR SW ON
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-147
STEP 3. Check the input signal (by using the pulse check
mode of the monitor).
Check the following switches and input signals:
Key reminder switch
Door switches
(1) 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."
(2) Check if diagnostic tool MB991958 sounds or not.
Q: When the key reminder switch, any door switch is
operated, does diagnostic tool MB991958 sound?
Buzzer of diagnostic tool MB991958 sounds normally. :
Replace the ETACS-ECU. The forgotten key
prevention function should work normally.
When the ignition key is removed and inserted,
diagnostic tool MB991958 does not sound. : Refer to
Inspection Procedure N-1 "ETACS-ECU does not
receive any signal from the key reminder switch
P.54B-432."
When one of the doors is opened and closed,
diagnostic tool MB991958 does not sound : Refer to
Inspection Procedure N-3 "ETACS-ECU does not
receive any signal from any of the door switches
P.54B-440." ITEM NAME CONDITION
key reminder switch Remove and reinsert the ignition key
Door switches Open or close one of the doors