Chery Fora (Elara A520). Manual — part 143

CHERY·A21 SERVICE MANUAL ENGINE EFI SYSTEM

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l Idle speed control

l Knock control

l Provide sensor power: 5V/100mA

l Closed loop control

l Control carbon canister solenoid valve

l Air conditioner switch

l engine malfunction indicator

l Fuel fix quantity modification

l Engine speed signal output(TN signal)

l Input of speed signal

l Malfunction self diagnosis

l Accept engine loading signal etc.

5)Definition of pin

Pin

point

Pin

Connection point

1

Oxygen sensor heating

42

Air intake temperature

2

Ignition coil 2

43

3

Ignition

44

Non persistent power

4

Oxygen sensor heating

45

Non persistent power

5

Ignition coil 1

46

Canister valve

6

Injection nozzle 4(cylinder No. 2)

47

Injection nozzle 3(cylinder

No.4)

7

Injection nozzle 2(cylinder No.3)

48

8

Engine speed

49

9

Coolant temperature

50

Fan control 1

10

Fuel consuming

51

electronically 2

11

Trouble light

52

12

Persistent power

53

electronically 1

13

Ignition coil

54

Electronic throttle valve

position

14

Main relay

55

Downstream oxygen sensor

15

Engine speed sensor A

56

CHERY·A21 SERVICE MANUAL ENGINE EFI SYSTEM

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16

Accelerator position sensor

57

17

Sensor 1

58

Brake switch

18

Upstream oxygen sensor

59

Speed signal

19

Knock sensor A

60

Medium switch

20

Knock sensor B

61

Power 1

21

Brake light

62

CAN communication

22

63

Non persistent power

23

Accelerating sensor

64

Electronic throttle valve

control

24

65

Electronic throttle valve

control

25

66

Electronic throttle valve

control

26

67

Electronic throttle valve

control

27

Injection nozzle 1(cylinder No.1)

68

Cooling fan

28

69

Air conditioner relay

29

70

Fuel pump relay

30

71

Diagnosis K cable

31

EOBD inspection light

72

32

5V power supply 2

73

Anti theft device

33

5V power supply 1

74

Clutch switch

34

Engine speed sensor B

75

Air conditioner switch

35

Sensor 3

76

Power steering switch

36

Sensor 2

77

Headlamp switch

37

Air flow sensor

78

Sensor

38

Electronic throttle valve control

79

Phase sensor

39

Engine coolant temperature sensor

80

Power 2

40

Accelerator position sensor

81

CAN communication

41

Air conditioner pressure

6)Normal working voltage: 9--16V

Normal working temperature: -40--70℃

7)Malfunction phenomena and diagnosis method

CHERY·A21 SERVICE MANUAL ENGINE EFI SYSTEM

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l Malfunction phenomena: idle speed not stable, accelerating not good, can not start, idle

speed is too high, exhaust gas exceed standard, difficult to start, air conditioner failure,
injector control failure, engine dies out etc..

l Reasons for general malfunction: 1, ECU component was burnt down caused by

overloading of the exterior connected electrical device; 2, circuit board was rust and
erode caused by water in ECU.

l Service notice: 1, do not disassemble ECU at random during the service; 2, disassemble

accumulator 5 minutes prior to disassemble ECU; 3, keep the disassembled ECU
carefully; 4, prohibit to connect any circuit to ECU connecting line.

l Simple measurement method:

1、(connect ECU joint)Read engine malfunction record by K line.

2、(disassemble ECU joint)Check the connecting line of ECU, and pay more attention to

check the power supply and ground line of ECU;

3、Check the working conditions of exterior sensor and its output signal and its circuit;

4、Check actuator and its circuit;

5、At last change ECU and have a test.

CHERY·A21 SERVICE MANUAL ENGINE EFI SYSTEM

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3.2 COOLANT TEMPERATURE SENSOR

1)exterior drawing and pin

This sensor has two exchangeable pins.

2)Purpose: The sensor provide the coolant
temperature signal to ECU for ignition timing
and modifying fuel injection of starting, idle
speed and normal working.

3)Installation position

Coolant temperature sensor was installed on the
water outlet of cylinder block and the copper
heat conducted socket was inserted into water.
There are thread on the socket, and screw in
coolant temperature sensor onto the threaded
hole on cylinder block by the hexagon head of
the socket. The maximum moment is 20Nm.

4)Working principle

This sensor is a thermistor of negative
temperature coefficient (NTC), and its value
will decrease with the coolant temperature
increasing but the changes are not linearity.
There are several different resistance values at
different temperature:

T(℃)

Resistance value(kΩ)

-10

8.62----10.28

20

2.37----2.63

80

0.299----0.345

5)Normal working temperature: -30----130 ℃

Normal working voltage: 5V DC

6)Malfunction phenomenon and diagnosis

method

l Malfunction phenomenon: Difficult to

start.

l Reasons of malfunction: man made

l Simple measurement method:

Chart 3-2 Outlook drawing of the

coolant temperature sensor

Chart 3-3 Circuit diagram of coolant

temperature sensor

Coolant Temperature Sensor