Mitsubishi Lancer Evolution X. Manual — part 30

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-145

.

FUNCTION

If the scan tool MB991958 cannot communicate with
the A/C-ECU <vehicles with A/C> or heater control
unit <vehicles without A/C>, this diagnosis result will
be set.

.

TROUBLE JUDGMENT CONDITIONS

If a communication flag is not set for the A/C-ECU
<vehicles with A/C> or heater control unit <vehicles
without A/C>, the ETACS-ECU determines that there
is a failure.

.

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector

(CAN1), A/C-ECU <vehicles with A/C> or heater
control unit <vehicles without A/C> connector
improperly connected]

• Malfunction of the wiring harness [open circuit

between the A/C-ECU <vehicles with A/C> or
heater control unit <vehicles without A/C> con-
nector and the joint connector (CAN1), power
supply circuit to the A/C-ECU <vehicles with
A/C> or heater control unit <vehicles without
A/C>]

• Malfunction of the A/C-ECU <vehicles with A/C>

or heater control unit <vehicles without A/C>

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set
• MB992006: Extra Fine Probe

STEP 1. Check joint connector (CAN1) C-105 and A/C-ECU
connector C-22 <vehicles with A/C> or heater control unit
connector C-53 <vehicles without A/C> for loose, corroded
or damaged terminals, or terminals pushed back in the
connector.

CAUTION

The strand end of the twisted wire should be within 10 cm
(4 inches) from the connector. For details refer to

P.54C-7

.

Q: Are joint connector (CAN1) C-105 and A/C-ECU

connector C-22 <vehicles with A/C> or heater control
unit connector C-53 <vehicles without A/C> in good
condition?
YES : Go to Step 2.
NO : Repair the damaged parts.

AC708951CE

Connector: C-22

C-22 (B)

AC708950

Connector: C-105

BL

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-146

STEP 2. Check the wiring harness between joint connector
(CAN1) C-105 and A/C-ECU connector C-22 <vehicles with
A/C> or heater control unit connector C-53 <vehicles
without A/C> for open circuit.

CAUTION

Strictly observe the specified wiring harness repair proce-
dure. For details refer to

P.54C-7

.

(1) Disconnect joint connector (CAN1) C-105 and A/C-ECU

connector C-22 <vehicles with A/C> or heater control unit
connector C-53 <vehicles without A/C>, and check the
wiring harness.

(2) Check the wiring harness between joint connector (CAN1)

C-105 (terminal 1) and A/C-ECU connector C-22 <vehicles
with A/C> or heater control unit connector C-53 <vehicles
without A/C> (terminal 11)

OK: Continuity exists (2 Ω or less)

(3) Check the wiring harness between joint connector (CAN1)

C-105 (terminal 12) and A/C-ECU connector C-22
<vehicles with A/C> or heater control unit connector C-53
<vehicles without A/C> (terminal 12)

OK: Continuity exists (2 Ω or less)

Q: Is the wiring harness between joint connector (CAN1)

C-105 and A/C-ECU connector C-22 <vehicles with A/C>
or heater control unit connector C-53 <vehicles without
A/C> in good condition?
YES : Check the power supply circuit of the A/C-ECU

<vehicles with A/C> or heater control unit <vehicles
without A/C>. Refer to GROUP 55, Diagnosis

P.55-121

<vehicles with A/C> or

P.55-96

<vehicles

without A/C>.

NO : Repair the wiring harness between joint connector

(CAN1) C-105 and A/C-ECU connector C-22
<vehicles with A/C> or heater control unit connector
C-53 <vehicles without A/C>.

AC709707

AC709707 CD

Harness side: C-105

Harness side: C-22

TEST HARNESS

TEST
HARNESS

AC709707 CE

Harness side: C-105

Harness side: C-22

TEST
HARNESS

TEST
HARNESS

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-147

DIAGNOSTIC ITEM 20: Diagnose when the scan tool cannot receive the data sent by radio and CD
player or CD changer.

CAUTION

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

CAN-B Communication Circuit

ETACS-ECU

INTERFACE
CIRCUIT

INTERFACE
CIRCUIT

CAN DRIVE
CIRCUIT

HANDS FREE
MODULE

OCCUPANT
CLASSIFICATION-
ECU

SATELLITE
RADIO TUNER

RADIO AND CD
PLAYER

NOTE

VEHICLES WITHOUT MITSUBISHI MULTI-COMMUNICATION SYSTEM (MMCS)
VEHICLES WITH MITSUBISHI MULTI-COMMUNICATION SYSTEM (MMCS)

CAN
TRANSCEIVER
CIRCUIT

CAN BOX UNIT

JOINT CONNECTOR
(CAN1)

FRONT SEAT
ASSEMBLY (LH)

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-148

.

FUNCTION

If the scan tool MB991958 cannot communicate with
the radio and CD player or CD changer, this diagno-
sis result will be set.

.

TROUBLE JUDGMENT CONDITIONS

If a communication flag is not set for the radio and
CD player or CD changer, the ETACS-ECU deter-
mines that there is a failure.

.

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector

(CAN1), radio and CD player or CD changer con-
nector improperly connected]

• Malfunction of the wiring harness [open circuit

between the radio and CD player or CD changer
connector and the joint connector (CAN1), power
supply circuit to the radio and CD player or CD
changer]

• Malfunction of the radio and CD player or CD

changer

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set
• MB992006: Extra Fine Probe

STEP 1. Check joint connector (CAN1) C-105 and radio and
CD player or CD changer connector C-107 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.

CAUTION

The strand end of the twisted wire should be within 10 cm
(4 inches) from the connector. For details refer to

P.54C-7

.

Q: Are joint connector (CAN1) C-105 and radio and CD

player or CD changer connector C-107 in good
condition?
YES : Go to Step 2.
NO : Repair the damaged parts.

AC708950

Connector: C-105

BL

AC708951BD

Connector: C-107