Mitsubishi Grandis. Manual — part 543

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54D-270

Diagnostic Item 8: Diagnose the CAN bus lines for short to earth <RH drive vehicles with ASC>

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.

A/C-ECU

CENTER DISPLAY

COMBINATION
METER

DIAGNOSIS
CONNECTOR

ASC-ECU

ENGINE-ECU<M/T>
ENGINE·A/T-ECU<A/T>

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

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54D-271

TROUBLE JUDGMENT

The CAN bus line has been shorted to earth if the
voltage between the CAN bus line (CAN_L or
CAN_H) and body earth is less than 1.0 V. In this
condition, an abnormal voltage may be measured at
CAN_L and CAN_H lines.

COMMENTS ON TROUBLE SYMPTOM

The wiring harness wire or connectors may have
loose, corroded, or damage terminals, or terminals
pushed back in the connector, or a ECU may be
defective.

POSSIBLE CAUSES

• Damaged harness wires and connectors

• Malfunction of the ETACS-ECU

• Malfunction of the combination meter

• Malfunction of the A/C-ECU

• Malfunction of the SRS-ECU

• Malfunction of the multi-centre display

• Malfunction of the steering wheel angle sensor

• Malfunction of the ASC-ECU

• Malfunction of the engine-ECU <M/T> or

engine-A/T-ECU <A/T>

ETACS-ECU

STEERING WHEEL
ANGLE SENSOR

SRS-ECU

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

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54D-272

DIAGNOSTIC PROCEDURE

STEP 1. Connector check: C-112 engine-ECU
<M/T> or engine-A/T-ECU <A/T> connector, C-02
combination meter connector and C-126
diagnosis connector

CAUTION

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

P.54D-8

.

Q: Are the check result normal?

YES :

Go to Step 2.

NO :

Repair the defective connector.

STEP 2. Resistance measurement at the C-126
diagnosis connector.

CAUTION

A digital multimeter should be used. For details
refer to

P.54D-8

.

CAUTION

The test wiring harness should be used. For
details refer to

P.54D-8

.

(1) Disconnect the engine-ECU <M/T> or

engine-A/T-ECU <A/T> connector and the
combination meter connector, and measure at
the wiring harness side.

CAUTION

When measuring the resistance, disconnect the
negative battery terminal. For details refer to

P.54D-8

.

(2) Ensure that the negative battery terminal is

AC310628AW

Harness side

Connector: C-112 <RHD>

C-112 (GR)

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

AC310632BC

Connectors: C-02, C-126 <RHD>

C-02

C-126 (B)

C-126 Harness side

C-02 Harness side

AC310628AW

Harness side

Connector: C-112 <RHD>

C-112 (GR)

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

AC310632BC

Connectors: C-02, C-126 <RHD>

C-02

C-126 (B)

C-126 Harness side

C-02 Harness side

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54D-273

disconnected.

(3) Resistance between C-126 diagnosis connector

terminal No.14 and body earth

OK: 1 k

Ω or more

(4) Resistance between C-126 diagnosis connector

terminal No.6 and body earth

OK: 1 k

Ω or more

Q: Are the check result normal?

YES <all of the measurement results show 1 k

Ω or

more> :

Follow diagnostic item 20 "Diagnose CAN

bus lines thoroughly." Refer to

P.54D-526

.

NO <The resistance between terminal No.14 and
body earth is less than 1 k

Ω> :

Go to Step 3.

NO <The resistance between terminal No.6 and
body earth is less than 1 k

Ω> :

Go to Step 30.

STEP 3. Connector check: C-125 intermediate
connector

CAUTION

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

P.54D-8

.

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the defective connector.

STEP 4. Resistance measurement at the C-125
intermediate connector.

CAUTION

A digital multimeter should be used. For details
refer to

P.54D-8

.

CAUTION

The test wiring harness should be used. For
details refer to

P.54D-8

.

(1) Disconnect the connector, and measure at its

male-side intermediate connector (at the front
wiring harness side).

CAUTION

When measuring the resistance, disconnect the
negative battery terminal. For details refer to

P.54D-8

.

(2) Ensure that the negative battery terminal is

AC209364

AC209364LC

Harness side: C-126
(Front side)

Test
harness

AC209364

AC209364

AC209364

AC209364

AC209364

AC209364LD

Harness side: C-126
(Front side)

Test
harness

AC310628AB

Connector: C-125 <RHD>

AC310628AB

Connector: C-125 <RHD>