Mitsubishi L200. Manual - part 182

TROUBLESHOOTING

DIESEL FUEL

13A-524

Inspection Procedure 26: PTC Heater Relay System <Vehicle with PTC Heater>

AKB00307

1

3

2

4

1

3

2

4

1

2

1

2

1

2

3

4

5 6 7 8 9

10 1112 13 14 15 16 17 18 19 20 21 22 23 24

25 26

27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72

43 44 45 46 47 48

73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96

R

R

Fusible link 25

3

A-141X

A-140X

2

4

1

PTC heater 
relay 1

PTC 
Heater 1

PTC 
Heater 2

PTC heater 
relay 2

3

2

4

1

2

43

1

J/B

7.5A

L-R

L-R

L-R

L-R

L-R

L-W

L-W

6

9

C-210

C-207

C-148

C-148

C-148

C-105

C-149

C-150

A-28

7

4

16

Ignition switch (IG2)

Y-GR

G-O

Y-G

Y-L

44

6

3

C-52

Engine-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: Grey
R: Red  P: Pink  V: Violet  PU: Purple  SI: Silver  

OFF

ON

OFF

ON

B

2

1

B

B-L

B-Y

2

1

PTC Heater Circuit

AB

A/C switch module <Manual A/C> 
or A/C-ECU <Automatic A/C>

TROUBLESHOOTING

DIESEL FUEL

13A-525

OPERATION

• When the PTC heater operation request signal 

(battery voltage) is input into the engine-ECU 
(terminal No. 6) from the A/C switch module 
<manual A/C> or A/C-ECU <automatic A/C>, the 
engine-ECU turns ON the PTC heater relay 1 and 
2 after satisfying all the operation conditions.
Operation conditions of PTC heater relay 1

a.  Engine coolant temperature is under 80

°C

b. 2 seconds later after the engine has start up.

c. The PTC heater request signal has been input 

continuously 2 seconds or more

d. The battery voltage continues to be 12.3 V or 

more for 12 seconds or more.

Operation conditions of PTC heater relay 2

a.  Engine coolant temperature is under 75

°C.

b. The PTC heater 1 has been ON continuously 

45 seconds or more.

c. Heater switch (warm up switch) is ON or vehi-

cle speed is 20km/h or more.

d. The battery voltage continues to be 12.9 V or 

more for 12 seconds or more.

PROBABLE CAUSES

• Failed PTC heater relay

• Failed PTC heater

• Damaged harness (Open circuit between PTC 

heater relay and engine-ECU, PTC heater relay 
and J/B, PTC heater relay and PTC heater, PTC 
heater and body earth, and open circuit between 
PTC heater relay and fusible link 25.

• Damaged connector (PTC heater relay connec-

tor, PTC heater connector, engine-ECU connec-
tor).

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

• Refer to Data List Reference Table 

P.13A-542

.

a. Item 76: PTC heater relay 1
b. Item 77: PTC heater relay 2

Q: Is the check result normal?

YES : 

Go to Step 2 .

NO : 

Check PTC heater system (Refer to 
GROUP 55A 

− Troubleshooting − Trouble 

Symptom Chart  <manual A/C>, GROUP 
55B 

− Troubleshooting − Trouble Symptom 

Chart  <automatic A/C>).

STEP 2. PTC heater 1 operation check

• Disconnect the C-105 connector.

• Using the jumper wire, connect terminal No. 43 to 

earth.

OK: The PTC heater 1 operates.

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Check PTC heater system (Refer to 
GROUP 55A 

− Troubleshooting − Trouble 

Symptom Chart  <manual A/C>, GROUP 
55B 

− Troubleshooting − Trouble Symptom 

Chart  <automatic A/C>).

AKA00089

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

43

44

45

46

47

48

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

C-105 (B)

C-105 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-105

AB

TROUBLESHOOTING

DIESEL FUEL

13A-526

STEP 3. PTC heater 2 operation check.

• Disconnect the C-105 connector.

• Using the jumper wire, connect terminal No. 44 to 

earth.

OK: The PTC heater 2 operates.

Q: Is the check result normal?

YES : 

Go to Step 4 .

NO : 

Check PTC heater system (Refer to 
GROUP 55A 

− Troubleshooting − Trouble 

Symptom Chart  <manual A/C>, GROUP 
55B 

− Troubleshooting − Trouble Symptom 

Chart  <automatic A/C>).

STEP 4. Connector check: C-105 engine-ECU 
connector.

Q: Is the check result normal?

YES : 

Go to Step 5 .

NO : 

Repair or replace.

STEP 5. Check the trouble symptoms.

Q: Does the trouble symptom persist?

YES : 

Replace the engine-ECU. When the engine-

ECU is replaced, write the chassis number 
(Refer to GROUP 00 

− Precautions Before 

Service 

− How to Perform Chassis Number 

Writing ). After replacing the engine-ECU, 
register the injector identification code and 
learn fuel injection (Refer to GROUP 00 

− 

Precautions Before Service 

− What The 

Common Rail Engine Learns ). After 
registering the injector identification code, 
the vehicle equipped with the DPF carries 
out the forcible DPF regeneration. (Refer to 
GROUP 17 

− Emission Control − Diesel 

Particulate Filter (DPF) System 

− Forcible 

DPF Regeneration ).

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Use Troubleshooting/

Inspection Service Points 

− How to Cope 

with Intermittent Malfunction ).

AKA00089

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

43

44

45

46

47

48

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

C-105 (B)

C-105 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-105

AB

AKA00089

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

43

44

45

46

47

48

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

C-105 (B)

C-105 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-105

AB

TROUBLESHOOTING

DIESEL FUEL

13A-527

Inspection Procedure 27: Blower Switch System <Euro5>

OPERATION

• The battery voltage is applied to the engine-ECU 

(terminal No. 125) from the blower switch.

FUNCTION

• When the blower fan is turned ON and the battery 

voltage is applied to the engine-ECU, the engine-
ECU increases the idle speed.

PROBABLE CAUSES

• Failed A/C system

• Open/short circuit or harness damage in blower 

switch circuit or loose connector contact

• Failed engine-ECU

AKB00331

101 102

103104 105 106107 108109 110 111112 113 114115

118119 120 121122 123124 125126127 128 129130

131132 133 134135 136137 138139140 141142 143

146147 148 149150 151152 153154155 156 157158

117

145

116

144

C-103

Blower switch

125

10

3

J/C (9)
C-10

L-B

G-Y

L-B

Blower Switch 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

Engine-ECU

AB

1*¹ or
4*²

C-52*¹ or
C-34*²

NOTE

*1: L.H. drive vehicles
*2: R.H. drive vehicles