Mitsubishi Lancer (4A9 engine). Manual — part 275

ACB02645

AL

C-04 (GR)

Connector: C-04 <LHD>

ACB02647

AH

C-04 (GR)

Connector: C-04 <RHD>

ACA00886

BE

Connector: C-301 <LHD>
ETACS-ECU

ACA00887

BF

Connector: C-301 <RHD>
ETACS-ECU

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-124

FUNCTION
If a failure is present in the wiring harness wires
between the ETACS-ECU connector and the joint
connector (CAN1), the ETACS-ECU connector and
the joint connector (CAN1), this diagnosis result will
be set.

TROUBLE JUDGEMENT CONDITIONS
If a communication flag is set for none of the ECUs
on the CAN-B line, the ETACS-ECU determines that
there is a failure.

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector

(CAN1) or ETACS-ECU connector improperly
connected]

• Malfunction of the wiring harness [open circuit

between the ETACS-ECU connector and the joint
connector (CAN1)]

• Malfunction of the ETACS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-04 joint connector
(CAN1) and C-301 ETACS-ECU connector

CAUTION

The strand end of the twist wire should be within
10 cm from the connector. For details refer to .

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the defective connector.

STEP 2. Check the wiring harness between C-301
ETACS-ECU connector and C-04 joint connector
(CAN1)

CAUTION

Strictly observe the specified wiring harness
repair procedure. For details refer to .
Disconnect ETACS-ECU connector and joint con-
nector (CAN1), and check the following wiring har-
ness for open circuit
(1) The wiring harness between C-301 ETACS-ECU

connector terminal No.6 and C-04 joint connector
(CAN1) terminal No.6 <CAN_H>

OK: Continuity exists (2

Ω or less)

(2) The wiring harness between C-301 ETACS-ECU

connector terminal No.7 and C-04 joint connector
(CAN1) terminal No.19 <CAN_L>

OK: Continuity exists (2

Ω or less)

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the wiring harness.

STEP 3. Trouble symptom check
Diagnose the CAN bus line, and check that normal
condition is displayed.

Q: Is the check result normal?

YES :

The trouble can be an intermittent

malfunction (Refer to GROUP 00

− How to

use Troubleshooting/inspection Service
Points

− How to Cope with Intermittent

Malfunction ).

NO :

Replace the ETACS-ECU.

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-125

Diagnosis Item 25: Short to power supply or earth, open circuit or line-to-line short in the CAN-B bus
lines

CAUTION

When servicing a CAN bus line, earth yourself by touching a metal object such as an unpainted water
pipe. If you fail to do, a component connected to the CAN bus line may be broken.

CAN-B Communication Circuit

ETACS-ECU

INTERFACE
CIRCUIT

CAN DRIVE
CIRCUIT

SRS-ECU

CPU

WCM

CAN BOX UNIT

KOS-ECU

CAN
TRANSCEIVER
CIRCUIT

CAN DRIVE
CIRCUIT

CAN DRIVE
CIRCUIT

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Grey R : Red P : Pink V : Violet PU : Purple SI : Silver

RADIO AND
CD PLAYER

CAN
TRANSCEIVER
CIRCUIT

INTERFACE
CIRCUIT

VEHICLES WITHOUT A/C

:

VEHICLES WITH A/C

:

VEHICLES WITH KOS

:

NOTE

VEHICLES WITH WCM

:

VEHICLES WITH RADIO AND CD PLAYER

:

VEHICLES WITHOUT AUDIO

:

VEHICLES WITH MMCS

:

COMBINATION
METER

HEATER CONTROL
PANEL
A/C-ECU

SPARE
CONNECTOR
(FOR AUDIO)

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-126

ACB02645

AK

C-04 (GR)

C-01

C-06

C-23

Connectors: C-01, C-04, C-06, C-23, C-32,
C-122 <LHD>

C-32 (GR)

C-122 (Y)

ACB02647

AG

C-103,
C-139

C-04 (GR)

C-01

C-06

Connectors: C-01, C-04, C-06, C-23, C-103,
C-122, C-139 <RHD>

C-23

C-122 (Y)

ACB02646

AF

C-15 (B),
C-60 (B)

Connectors: C-15, C-54, C-60, C-103, C-139
<LHD>

C-54 (G)

C-103,
C-139

ACB02648

AG

C-15 (B)

Connector: C-15<RHD>

ACA00886

BE

Connector: C-301 <LHD>
ETACS-ECU

ACA00887

BF

Connector: C-301 <RHD>
ETACS-ECU

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-127

FUNCTION
If a short to power supply or earth, open circuit or
line-to-line short is present at either CAN_H or
CAN_L side on the CAN-B lines, this diagnosis result
will be set.

TROUBLE JUDGEMENT CONDITIONS
When CAN-B lines communication is normal, and
diagnosis code U0019 is set in one or more of the
ECUs, the ETACS-ECU determines that there is a
failure.

TROUBLESHOOTING HINTS

• Malfunction of the connector (short to power sup-

ply or earth in connector or improperly con-
nected)

• Malfunction of the wiring harness (short to power

supply or earth, open circuit or line-to-line short in
CAN bus lines)

• Faulty ECU(s) (internal short to power supply or

earth)

DIAGNOSIS PROCEDURE

STEP 1. Checking short to earth (resistance
measurement)
NOTE: This check determines whether there is a
short to earth in the CAN-B bus line. If a short to
earth is present in either the CAN_H or CAN_L line,
check the appropriate line only.

CAUTION

• Disconnect the negative battery terminal. For

details refer to .

• A digital multimeter should be used. For

details refer to .

• The test wiring harness should be used. For

details refer to .

(1) Disconnect C-301 ETACS-ECU connector, and

measure at the wiring harness side.

(2) Measure the resistance between C-301 ETACS-

ECU connector terminal No.6 and body earth.