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Home >> Nissan-Datsun >> 2021 >> NV2500 HD S >> Repair and Diagnosis >> External Pages >> Different car >> Section 543 (Heater & Air Conditioning Control System (DTC/Circuit Diagnosis)) >> DTC/Circuit Diagnosis >> DTC B257C: Ambient Sensor >> DTC Description >> Description

DTC Description: Description

WARNING: This page is about a different car, the 2019 Nissan NV3500 HD, 2019 Nissan NV2500 HD, and 2019 Nissan NV1500. However, it is still accessible from the selected car via links, so may be relevant.

Ambient Sensor 

AD Counts

(sent on CAN)

Deg deg. C

AD Counts

(sent on CAN)

Deg deg. C

10

-30.00

53

13.00

11

-29.00

54

14.00

12

-28.00

55

15.00

13

-27.00

56

16.00

14

-26.00

57

17.00

15

-25.00

58

18.00

16

-24.00

59

19.00

17

-23.00

60

20.00

18

-22.00

61

21.00

19

-21.00

62

22.00

20

-20.00

63

23.00

21

-19.00

64

24.00

22

-18.00

65

25.00

23

-17.00

66

26.00

24

-16.00

67

27.00

25

-15.00

68

28.00

26

-14.00

69

29.00

27

-13.00

70

30.00

28

-12.00

71

31.00

29

-11.00

72

32.00

30

-10.00

73

33.00

31

-9.00

74

34.00

32

-8.00

75

35.00

33

-7.00

76

36.00

34

-6.00

77

37.00

35

-5.00

78

38.00

36

-4.00

79

39.00

37

-3.00

80

40.00

38

-2.00

81

41.00

39

-1.00

82

42.00

40

-0.00

83

43.00

41

1.00

84

44.00

42

2.00

85

45.00

43

3.00

86

46.00

44

4.00

87

47.00

45

5.00

88

48.00

46

6.00

89

49.00

47

7.00

90

50.00

48

8.00

91

51.00

49

9.00

92

52.00

50

10.00

93

53.00

51

11.00

94

54.00

52

12.00

95

55.00

Ambient temperature input process 

The front air control contains a processing circuit for the ambient sensor input. However, when the temperature detected by the ambient sensor increases quickly, the processing circuit retards the front air control function. It only allows the front air control to recognize an ambient temperature increase of 0.33 deg. C (0.6 deg. F) per 100 seconds.

As an example, consider stopping for a few minutes after high speed driving. Although the actual ambient temperature has not changed, the temperature detected by the ambient sensor increases. This is because the heat from the engine compartment can radiate to the front bumper area, the location of the ambient sensor.