Mitsubishi Grandis. Manual — part 503

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54D-110

Diagnostic Item 3: Diagnose the CAN bus lines for short to power supply <RH drive vehicles without
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

ABS-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-111

TROUBLE JUDGMENT

Short to power supply may be present when the
voltage between the CAN bus line (CAN_L or
CAN_H) and body earth is more than 4.0 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 ABS-ECU

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

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

ETACS-ECU

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-112

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. Voltage 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.

(2) Connect the negative battery terminal, and turn

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-113

the ignition switch to the ON position.

(3) Voltage between C-126 diagnosis connector

terminal No.14 and body earth

OK: 4.0 V or less

(4) Voltage between C-126 diagnosis connector

terminal No.6 and body earth

OK: 4.0 V or less

(5) Disconnect the negative battery terminal.

Q: Are the check result normal?

YES <all of the measurement results show 4.0 V or
less> :

Follow diagnostic item 19, Diagnose CAN

bus lines thoroughly. Refer to

P.54D-502

.

NO <The voltage between terminal No.14 and body
earth is more than 4.0 V> :

Go to Step 3 .

NO <The voltage between terminal No.6 and body
earth is more than 4.0 V> :

Go to Step 28 .

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. Voltage 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).

(2) Connect the negative battery terminal, and turn

AC209365JP

8

16

15

7

5

13 14

6

12

4

2

10 11

3

9

1

Harness side: C-126
(Front side)

Test
Harness

AC209365

Harness side: C-126
(Front side)

Test
harness

JO

Y

8

16

15

7

5

1314

6

12

4

2

1011

3

9

1

AC310628AB

Connector: C-125 <RHD>

AC310628AB

Connector: C-125 <RHD>