SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-10
SWS DIAGNOSIS
GENERAL DESCRIPTION
BEFORE CARRYING OUT TROUBLESHOOTINGM1549014700710
Before carrying out troubleshooting, check the fol-
lowing two items.
Make sure that the ETACS-ECU, the junction
block (J/B), the front-ECU and the engine com-
partment relay box are connected securely.
Make sure that fuses and fusible links related to
relevant systems are not blown.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
DIAGNOSTIC FUNCTIONM1549028900245
ON-BOARD DIAGNOSTICS
If an error occurs in the ECU or the SWS or CAN
communication line which performs the SWS or CAN
communication, the DTC is memorized in
ETACS-ECU. The DTCs have 11 items. The DTCs
are checked to connect diagnostic tool MB991958
(MUT-III sub assembly). The memorised DTCs are
not erased even if the ignition switch is turned to the
LOCK (OFF) position. The DTCs are erased to oper-
ate diagnostic tool MB991958 (MUT-III sub assem-
bly).NOTE:
*1: For vehicles that do not have a sunroof,
the diagnosis code is always sent but it does not indi-
cate a problem.
NOTE:
*2: The diagnosis code for the current prob-
lem is not sent.
NOTE:
*3: For vehicles that do not have a multi cen-
ter display (middle grade type), the diagnosis code is
always sent but it does not indicate a problem.
HOW TO CONNECT THE DIAGNOSTIC TOOL
(MUT-III)
Required Special Tools:
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 DTC CODE TROUBLE CONTENT
001 or U1700 Malfunction of SWS communication line or ETACS-ECU
002 or U1701 Malfunction of column switch
003 or U1702 Malfunction of front-ECU
004
*1 or U1073Malfunction of sunroof-ECU
010
*2 or U1073Bus Off
011 or U1100 Engine ECU time-out
012 or U1101 A/T ECU time-out
013 or U1110 A/C-ECU time-out
014 or U1108 Combination meter time-out
015
*3 or U1111Multi center display unit time-out
021 or U1128 Failure information on combination meter
SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-13
When the SWS communication line is monitored,
you can determine whether the problem lies in the
input or output signal circuit system by checking
whether communication data is correct:
If the switch condition does not meet the service
data display, the input signal is defective.
If the switch condition meets the service data dis-
play, the output signal system is defective.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80NOTE: In addition to the function-specific diag-
nostic menu, a service data menu is available for
SWS monitor service data to check all items for
each ECU.
6. Check the input signal circuit system
Check the relevant switch, sensor, input
signal-side ECU and their wiring harness and
connector.
7. Check the output signal circuit system
Check an output signal-side ECU, electrical load
components and their wiring harness and
connector.
HOW TO CONNECT SWS MONITORM1549014800706
Required Special Tools:
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: Probe Harness
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 the main harness A MB991910 before
connecting the SWS monitor harness (for column-ECU)
MB991812. Be sure to connect SWS monitor cartridge
MB991806 after turning on the V.C.I. MB991924.
1. Ensure that the ignition switch is at the "LOCK" (OFF)
position.
2. Start up the personal computer.
3. Connect special tool MB991827 to special tool MB991824
and the personal computer.
4. Connect special tool MB991910 to special tool MB991824.
5. Connect special tool MB991910 to the data link connector.
DIAGNOSTIC TROUBLE CODE CHART
SIMPLIFIED WIRING SYSTEM (SWS)54B-25
DIAGNOSTIC TROUBLE CODE CHARTM1549000700461
DIAGNOSTIC TROUBLE CODE PROCEDURES
DTC 001: Trouble in SWS communication line or ETACS-ECU
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."
If DTC 001 is set in the ETACS-ECU, always diag-
nose the CAN main bus line.
.
TROUBLE JUDGMENT
The ETACS-ECU communicates with the column
switch, the front-ECU and the sunroof-ECU through
the SWS communication line. If there is any trouble
in the SWS communication line and the
ETACS-ECU, DTC 001 will be set.
.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
The wiring harness wire or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector, or the
ETACS-ECU may be defective.Past trouble
If DTC 001 is set as past trouble, carry out diag-
nosis with particular emphasis on wiring and con-
nector(s) in the SWS communication line. For
diagnosis procedures, refer to "How to cope with
past trouble" (Refer to GROUP 00, How to treat
past trouble P.00-16).
.
TROUBLESHOOTING HINTS
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80 DIAGNOSTIC TROUBLE
CODE NO.DESCRIPTION REFERENCE
PA G E
001 (U1700) Trouble in SWS communication line or ETACS-ECU
P.54B-25
002 (U1701) Trouble in column switch
P.54B-29
003 (U1702) Trouble in front-ECU
P.54B-32
004 (U1703) Trouble in sunroof-ECU
P.54B-35
010 (U1073) Bus Off
P.54B-38
011 (U1100) Engine ECU time-out (related to engine)
P.54B-39
012 (U1101) A/T ECU time-out (related to A/T)
013 (U1110) A/C-ECU time-out
P.54B-43
014 (U1108) Combination meter time-out
P.54B-46
015 (U1111) Multi center display unit time-out
P.54B-50
021 (U1128) Failure information on combination meter
P.54B-53
DIAGNOSTIC TROUBLE CODE PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-29
DTC 002: Trouble in Column Switch
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."
If DTC 002 is set in the ETACS-ECU, always diag-
nose the CAN main bus line.
.
TROUBLE JUDGMENT
The ETACS-ECU communicates with the column
switch through the SWS communication line. If there
is any trouble in that communication, DTC 002 will be
set.
.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
The column switch, the ETACS-ECU, connec-
tor(s), or wiring harness between the two may be
defective.Past trouble
If DTC 002 is set as past trouble, carry out diag-
nosis with particular emphasis on wiring and con-
nector(s) between the column switch and the
ETACS-ECU or power supply to the column
switch. For diagnosis procedures, refer to "How
to cope with past trouble" (Refer to GROUP 00,
How to treat past trouble P.00-16).
.
TROUBLESHOOTING HINTS
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
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: Probe Harness
DIAGNOSTIC TROUBLE CODE PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-32
DTC 003: Trouble in Front-ECU
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."
If DTC 003 is set in the ETACS-ECU, always diag-
nose the CAN main bus line.
.
TROUBLE JUDGMENT
The ETACS-ECU communicates with the front-ECU
through the SWS communication line. If there is any
trouble in that communication, DTC 003 will be set.
.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
The front-ECU, the ETACS-ECU, connector(s), or
wiring harness between the two may be defec-
tive.Past trouble
If DTC 003 is set as past trouble, carry out diag-
nosis with particular emphasis on wiring and con-
nector(s) between the front-ECU and the
ETACS-ECU or power supply to the front-ECU.
For diagnosis procedures, refer to "How to cope
with past trouble" (Refer to GROUP 00, How to
treat past trouble P.00-16).
.
TROUBLESHOOTING HINTS
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
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: Probe Harness
DIAGNOSTIC TROUBLE CODE PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-35
DTC 004: Trouble in Sunroof-ECU
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."
DTC 004 may also set on vehicles without sun-
roof, but there is no fault.
If DTC 004 is set in the ETACS-ECU, always diag-
nose the CAN main bus line.
.
TROUBLE JUDGMENT
The ETACS-ECU communicates with the front-ECU
through the SWS communication line. If there is any
trouble in that communication, DTC 004 will be set.
.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
The sunroof-ECU, the ETACS-ECU, connec-
tor(s), or wiring harness between the two may be
defective.Past trouble
If DTC 004 is set as past trouble, carry out diag-
nosis with particular emphasis on wiring and con-
nector(s) between the sunroof-ECU and the
ETACS-ECU or power supply to the sun-
roof-ECU. For diagnosis procedures, refer to
"How to cope with past trouble" (Refer to GROUP
00, How to treat past trouble P.00-16).
.
TROUBLESHOOTING HINTS
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
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: Probe Harness
DIAGNOSTIC TROUBLE CODE PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-38
DTC 010 (U1073): Bus Off
If DTC (U1073) is set in the ETACS-ECU, always
diagnose the CAN main bus line.
If the DTC is set as past trouble, the ECU cannot
be defective. Do not replace it.
.
TROUBLE JUDGMENT
DTC 010 (U1073) will be stored when the
ETACS-ECU ceases CAN communication (bus off)
and then resumes the communication by turning the
ignition switch to the "LOCK" (OFF) position
.
TECHNICAL DESCRIPTION (COMMENT)
Carry out diagnosis with particular emphasis on wir-
ing and connector(s) in the CAN bus lines. For diag-
nosis procedures, refer to "How to cope with past
trouble" (Refer to GROUP 00, How to treat past trou-
ble P.00-16).
.
TROUBLESHOOTING HINTS
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
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. Using diagnostic tool MB991958, diagnose the
CAN bus line.
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 diagnostic tool MB991958. Refer to "How to
connect SWS monitor P.54B-13."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES : Go to Step 2.
NO : Repair the CAN bus line (Refer to GROUP 54C,
Diagnosis P.54C-5).
DIAGNOSTIC TROUBLE CODE PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-39
STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Replace the ETACS-ECU. After replacement, verify
that the DTC is not reset.
NO : There is an intermittent malfunction such as poor
engaged connector(s) or open circuit (Refer to
GROUP 00, How to Cope with Intermittent
Malfunction P.00-14).
DTC 011 (U1100): Engine ECU Time-out
DTC 012 (U1101): A/T ECU Time-out
If DTC (U1100) or 012 is set in the ETACS-ECU,
always diagnose the CAN main bus line.
Whenever the ECU is replaced, ensure that the
communication circuit is normal.
.
TROUBLE JUDGMENT
DTC 011 (U1100)
The ETACS-ECU receives engine control sys-
tem-related signal from the Engine ECU. If the
ECU cannot receive the signal, DTC 011
(U1100) will be set. DTC 012 (U1101)
The ETACS-ECU receives automatic transaxle
control system-related signal from the A/T ECU.
If automatic transaxle control system-related sig-
nal cannot be received, DTC 012 (U1101) will be
set.
.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
Connector(s) or wiring harness in the CAN bus
lines between the Engine ECU or A/T ECU and
the ETACS-ECU, the power supply system to the
Engine ECU or A/T ECU, the Engine ECU or A/T
ECU itself, or the ETACS-ECU may be defective.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80