SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-12
HOW TO DIAGNOSE THE CAN BUS LINES
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
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 to the data link
connector.
2. Turn the ignition switch to the "ON" position.
3. Select "CAN bus diagnosis" from the start-up screen.
4. When the vehicle information is displayed, confirm that it
matches the vehicle being diagnosed.
If they match, go to step 8.
If not, go to step 5.
5. Select the "view vehicle information" button.
6. Enter the vehicle information and select the "OK" button.
7. When the vehicle information is displayed, confirm again
that it matches the vehicle being diagnosed.
If they match, go to step 8.
If not, go to step 5.
8. Select the "OK" button.
9. When the optional equipment screen is displayed, choose
the one which the vehicle is fitted with, and then select the
"OK" button.
SWS DIAGNOSTIC TROUBLESHOOTING STRATEGYM1549000500906
1. Gather information about the problem from the
customer.
2. Verify that the condition described by the
customer exists.
NOTE: If an error occurs in the SWS communica-
tion line, the ECU isolated from the communica-
tion line performs a fail-safe or backup operation,
so the problem may not match the one shown in
the Trouble Symptom Chart. However, the cause
of the failure can be tracked down by performing
the following troubleshooting with the SWS moni-
tor.
3. Version number and destination check
Check whether the SWS version number and
destination meet the vehicle specifications. If they
are different, replace the ETACS-ECU with a
correct one.
4. Use diagnostic tool MB991958 (MUT-III Sub
Assembly) to select "ECU COMM Check" on the
SWS monitor display.Check whether the communication status of the
input- or output-signal-side ECU associated with
the defective function is normal.
If "OK" is displayed for all related ECUs, they
communicate with each other normally and the
input or output signal circuit system may be
defective. Therefore, check SWS monitor service
data.
If "NG" is displayed for any of the related ECUs,
something may be wrong with the ECU for which
"NG" appears, its power supply or grounding sys-
tem, or a wiring harness or connector between
the SWS monitor and the ECU. Check the wiring
harness and connectors associated with the ECU
and examine the ECU itself.
5. Service data on the SWS monitor
Select the defective function from the
function-specific diagnostic menu, and check the
service data that appears for each function item.
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 PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-28
STEP 3. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the following ECUs:
ETACS-ECU
Column switch (column-ECU)
Front-ECU
Sunroof-ECU
Connect special tool MB991910 before connecting special
tool MB991812. Be sure to connect special tool MB991806
after turning on special tool MB991824.
(1) Connect the SWS monitor. 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" menus for the "ETACS ECU",
"COLUMN ECU", "FRONT ECU" and "SUNROOF ECU"
menus.
Q: Are "OK" displayed for the "ETACS ECU," "COLUMN
ECU," "FRONT ECU" and "SUNROOF ECU" menus?
"OK" are displayed for all the items : It is determined that
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).
"NG" is displayed for the "ETACS ECU" menu : Refer to
Inspection Procedure A-3 "Communication with the
ETACS-ECU is not possible P.54B-74."
"NG" is displayed for the "COLUMN ECU" menu : Refer
to Inspection Procedure A-2 "Communication with the
column switch (column-ECU) is not possible
P.54B-68."
"NG" is displayed for the "FRONT ECU" menu : Refer to
Inspection Procedure A-4 "Communication with the
front-ECU is not possible P.54B-80."
"NG" is displayed for the "SUNROOF ECU" menu :
Refer to Inspection Procedure A-5 "Communication
with the sunroof-ECU is not possible P.54B-87."
DIAGNOSTIC TROUBLE CODE PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-31
STEP 3. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the following ECUs:
Column-ECU
ETACS-ECU
Connect special tool MB991910 before connecting special
tool MB991812. Be sure to connect special tool MB991806
after turning on special tool MB991824.
(1) Connect the SWS monitor. 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" menus for both the "COLUMN ECU"
and the "ETACS ECU" menus.
Q: Are "OK" displayed for both the "COLUMN ECU" and
"ETACS ECU" menus?
"OK" are displayed for all the items : It is determined that
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).
"NG" is displayed for the "COLUMN ECU" menu : Refer
to Inspection Procedure A-2 "Communication with the
column switch (column-ECU) is not possible
P.54B-68."
"NG" is displayed for the "ETACS ECU" menu : Refer to
Inspection Procedure A-3 "Communication with the
ETACS-ECU is not possible P.54B-74."
DIAGNOSTIC TROUBLE CODE PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-34
STEP 3. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the following ECUs:
Front-ECU
ETACS-ECU
Connect special tool MB991910 before connecting special
tool MB991812. Be sure to connect special tool MB991806
after turning on special tool MB991824.
(1) Connect the SWS monitor. 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" menus for both the "ETACS ECU"
and the "FRONT ECU" menus.
Q: Are "OK" displayed for both the "ETACS ECU" and
"FRONT ECU" menus?
"OK" are displayed for all the items : It is determined that
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).
"NG" is displayed for the "ETACS ECU" menu : Refer to
Inspection Procedure A-3 "Communication with the
ETACS ECU is not possible P.54B-74."
"NG" is displayed for the "FRONT ECU" menu : Refer to
Inspection Procedure A-4 "Communication with the
front-ECU is not possible P.54B-80."
DIAGNOSTIC TROUBLE CODE PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-37
STEP 3. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the following ECUs:
Sunroof-ECU
ETACS-ECU
Connect special tool MB991910 before connecting special
tool MB991812. Be sure to connect special tool MB991806
after turning on special tool MB991824.
(1) Connect the SWS monitor. 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" menus for both the "SUNROOF ECU"
and the "ETACS ECU" menus.
Q: Are "OK" displayed for both the "SUNROOF ECU" and
"ETACS ECU" menus?
"OK" are displayed for all the items : It is determined that
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).
"NG" is displayed for the "SUNROOF ECU" menu :
Refer to Inspection Procedure A-5 "communication
with the sunroof-ECU is not possible P.54B-87."
"NG" is displayed for the "ETACS ECU" menu : Refer to
Inspection Procedure A-3 "Communication with the
ETACS-ECU is not possible P.54B-74."
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-69
STEP 1. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the following ECUs:
ETACS-ECU
Column-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 "ON" 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" menus for both the "ETACS ECU"
and the "COLUMN ECU" menus.
Q: Is "OK" displayed for both the "ETACS ECU" and
"COLUMN ECU" menus?
"OK" is displayed for all the items : Go to Step 2.
"NG" is displayed for the "COLUMN ECU" menu : Go to
St e p 6 .
"NG" is displayed for the "ETACS ECU" menu : Refer to
Inspection Procedure A-3 "Communication with the
ETACS-ECU is not possible P.54B-74."
"NG" is displayed for all the items : Refer to Inspection
Procedure A-3 "Communication with the ETACS-ECU
is not possible P.54B-74."
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-82
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."