Mitsubishi Evolution X. Manual — part 1094

EXPLANATION ABOUT THE SCAN TOOL (M.U.T.-III) CAN BUS DIAGNOSTICS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-11

ECU C

CAN bus line
(g) and power
supply
system to
ECU C

The ECU C communicates with
scan tool MB991958 via CAN
bus lines (b), (c), (d) and (g).
Scan tool MB991958 judges
that CAN bus lines (b), (c) and
(d) are normal, because it can
communicate with ECUs B and
D. Possible trouble may be
present in CAN bus line (g) or
the power supply system to
ECU C.

ECU C and
ECU D

Trouble in
CAN bus line
(d)

ECUs C and D communicate
with scan tool MB991958 via
CAN bus lines (b), (c), (d), (e)
and (g). Scan tool MB991958
judges that CAN bus lines (b)
and (c) are normal, because it
can communicate with ECU B.
Possible trouble may be
present in CAN bus line (d), (e)
or (g) or the power supply
system to ECU C and ECU D.
CAN bus line (d) is shared by
ECUs C and D when they
communicate with scan tool
MB991958, so CAN bus line (d)
is suspected as ultimate cause.
CAN bus line (g) or (e) and
power supply systems to ECU
C or D are also suspected as
second cause.

ECU B and
ECU D

CAN bus line
(e) or (f) and
power supply
system to
ECU B or D

ECUs B and D communicate
with scan tool MB991958 via
CAN bus lines (b), (c), (d), (e)
and (f). Scan tool MB991958
judges that CAN bus lines (b),
(c) and (d) are normal, because
it can communicate with ECU
C. Possible trouble may be
present in CAN bus line (f) or
(e) and power supply system to
ECU B or D are also suspected
as second cause.

ECU which
cannot
communicate
with the scan
tool

Possible
trouble spot

Logic for narrowing down trouble spot

AC204742BI

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

ETACS-ECU
(Gateway)

Data link
connector

AC204742BJ

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

ETACS-ECU
(Gateway)

Data link
connector

AC204742BK

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

ETACS-ECU
(Gateway)

Data link
connector

EXPLANATION ABOUT THE SCAN TOOL (M.U.T.-III) CAN BUS DIAGNOSTICS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-12

2. Pinpoint possible trouble spot according to

diagnostic trouble code
If diagnostic trouble code related to CAN
communication is set as past trouble, isolate
opens as described below.
NOTE: If you pinpoint trouble spot according to
diagnostic trouble code, you should use time-out
diagnostic trouble code. Diagnostic trouble code
related to failure information is set when the data
to be set contains an error, so CAN bus line itself
is probably normal.

NOTE: Time-out diagnostic trouble codes are
stored in each ECU memory individually. There-
fore, it is possible that these diagnostic trouble
codes have not been set simultaneously. If the
trouble spot cannot be found when you diagnose
by judging from multiple diagnostic trouble codes,
check the communication lines between each
ECU.

All ECU
(except
ETACS-ECU)

CAN bus line
(b)

The other ECUs except the
ETACS-ECU use CAN bus
lines (b) and (h) when they
communicate with scan tool
MB991958. It must be assumed
that CAN bus line (b) is
defective since the
ETACS-ECU can communicate
with scan tool MB991958.

ECU which
cannot
communicate
with the scan
tool

Possible
trouble spot

Logic for narrowing down trouble spot

AC204742BP

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

ETACS-ECU
(Gateway)

Data link
connector

Diagnostic
trouble code to
be set

Possible
trouble spot

Logic for narrowing down trouble spot

Time-out
diagnostic
trouble code
associated with
ECU D is stored
in ECU A, ECU B
and ECU C.

Trouble in
CAN bus line
(e) and power
supply system
to ECU D

When time-out diagnostic
trouble code associated with
ECU D is stored in ECU A, B
and C, or time-out diagnostic
trouble code associated with
ECUs A, B and C is stored in
ECU D, or "bus off"
diagnostic trouble code is
stored in ECU D, CAN bus
line (e) is suspected. When
diagnostic trouble code is not
stored in ECU D, the power
supply to ECU D is
suspected.

Time-out
diagnostic
trouble code
associated with
ECUs A, B and C
is stored in ECU
D.
"Bus off"
diagnostic
trouble code is
stored in ECU D.

AC204742BL

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

ETACS-ECU
(Gateway)

Data link
connector

EXPLANATION ABOUT THE SCAN TOOL (M.U.T.-III) CAN BUS DIAGNOSTICS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-13

Time-out
diagnostic
trouble code
associated with
ECU A is stored
in ECUs B, C and
D.

Trouble in
CAN bus line
(a) or (c) and
power supply
system to
ECU A.

When time-out diagnostic
trouble code associated with
ECU A is stored in ECUs B, C
and D, or time-out diagnostic
trouble code associated with
ECUs B, C and D is stored in
ECU A, or "bus off" diagnostic
trouble code is stored in ECU
A, CAN bus line (a) or (c) is
suspected. When diagnostic
trouble code is not stored in
ECU A, the power supply to
ECU A is suspected.

Time-out
diagnostic
trouble code
associated with
ECUs B, C and D
is stored in ECU
A.
"Bus off"
diagnostic
trouble code is
stored in ECU A.
Time-out
diagnostic
trouble codes
associated with
ECUs C and D
are stored in
ECU A and ECU
B.

Trouble in
CAN bus line
(d)

If time-out diagnostic trouble
codes associated with ECUs
C and D are stored in ECUs A
and B, or time-out codes
associated with ECUs A and
B are stored in ECUs C and
D, CAN bus line (d) is
suspected. CAN bus line (g)
or (e) and power supply
systems to ECU C or D are
also suspected as second
cause.

Time-out
diagnostic
trouble codes
associated with
ECUs A and B
are stored in
ECU C and ECU
D.
Time-out
diagnostic
trouble codes
associated with
ECUs A, B, C
and D are stored
in ETACS-ECU.

Trouble in
CAN bus line
(b)

It must be assumed that a
fault was present in CAN bus
line (b) when the
ETACS-ECU has set a
time-out diagnostic trouble
code for ECU A, B, C or D.

Time-out
diagnostic
trouble codes
associated with
ETACS-ECU is
stored in ECU A,
B, C and ECU D.

Diagnostic
trouble code to
be set

Possible
trouble spot

Logic for narrowing down trouble spot

AC204742BM

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

ETACS-ECU
(Gateway)

Data link
connector

AC204742BN

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

ETACS-ECU
(Gateway)

Data link
connector

AC204742BP

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

ETACS-ECU
(Gateway)

Data link
connector

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-14

DIAGNOSIS

CAN BUS DIAGNOSTICS TABLE

M1548300200914

CAUTION

A diagnostic trouble code may not also be set in
the CAN-B lines under the conditions below. If no
diagnostic trouble code has been set due to elec-
trical noise, confirm diagnosis item 27

P.54C-195

.

• Open circuit at the CAN_H side of the CAN-B

bus lines

• Open circuit at the CAN_L side of the CAN-B

bus line

• Short to ground at the CAN_H side of the

CAN-B bus line

CAUTION

During diagnosis, a diagnostic trouble code
associated with another system may be set when
the ignition switch is turned on with connector(s)
disconnected. After completing the repair, con-
firm all systems for diagnostic trouble code(s). If
diagnostic trouble code(s) are set, erase them all.
This diagnosis applies only to the CAN bus lines. If a
different system is defective, proceed to the applica-
ble diagnosis section for each system. Observe the
diagnosis procedure below only when the CAN bus
line is defective.

Scan tool screen

Diagnosis detail

Reference
page

(The ECUs that are not adopted are not
displayed.)

Comment

Short circuit to
battery in red
displayed area is
estimated.

Diagnosis Item 1
Diagnose when the
scan tool cannot receive
the data sent by
ETACS-ECU.

P.54C-27

AC709520AB

M.U.T.

J/C (3)

SAS

S-AWC

J/C (2)

KOS/WCM

SRS

A/C

AUDIO

MMCS

Sat Radio

HFM

OCM

METER

ASC

ENGINE

J/C (1)

ETACS

: Red section on screen

<M/T>

AC709521

ETACS

AB

M.U.T.

J/C (3)

SAS

S-AWC

J/C (2)

KOS/WCM

SRS

A/C

AUDIO

MMCS

Sat Radio

HFM

OCM

METER

ASC

LEVER

J/C (4)

ENGINE

J/C (1)

: Red section on screen

<TC-SST>

TC-SST