Mitsubishi Grandis. Manual — part 519

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54D-174

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 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-175

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

AC310615

AS

Harness side

Connector: C-112 <LHD>

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

AC310614

BJ

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

C-02

C-126 (B)

C-126 Harness side

C-02 Harness side

AC310615

AS

Harness side

Connector: C-112 <LHD>

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

AC310614

BJ

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

C-02

C-126 (B)

C-126 Harness side

C-02 Harness side

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54D-176

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 17, Diagnose CAN

bus lines thoroughly. Refer to

P.54D-452

.

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 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. 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

AC310613

AD

Connector: C-125 <LHD>

AC310613

AD

Connector: C-125 <LHD>

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54D-177

disconnected.

(3) Resistance between C-125 intermediate

connector terminal No.27 and body earth

OK: 1 k

Ω or more

Q: Is the check result normal?

YES :

<1 k

Ω or more> Go to Step 5.

NO :

<less than 1 k

Ω> Go to Step 20.

STEP 5. Connector check: C-09 joint connector
(CAN2)

CAUTION

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

P.54D-8

.

When checking the joint connector, ensure that its
wiring harness side and its short pins are not
damaged.

Q: Is the check result normal?

YES :

Go to Step 6 .

NO :

Repair a defective connector or replace the
joint connector.

STEP 6. Resistance measurement at C-09 joint
connector (CAN2).

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 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

disconnected.

(3) Resistance between C-09 joint connector (CAN2)

AC209364LE

Male side: C-125

Test harness

AC310615

AU

Harness side

Connector: C-09 <LHD>

C-09 (GR)

AC209350

1

12

2

13

3

14

4

15

5

16

6

17

7

18

8

19

9

20

10

21

11

22

AB

Short pin

AC310615

AU

Harness side

Connector: C-09 <LHD>

C-09 (GR)

AC209364LG

Harness side: C-09

Test
harness