Chery A15. Manual - part 31

Manifold absolute pressure signal is unreliable 
Engine coolant temperature signal is unreliable.   
Injector driver stage failure 
After oxygen sensor failure mark is set, fuel 
quantification closed-loop control is shut down, and 
the primitive fuel injection time stored in ECU is used 
to carry out fuel quantification. 

 

Installation hints: the tightening torque of oxygen 
sensor is 50-60Nm, a layer of rust preventive oil shall 
be applied on oxygen sensor after replacing so as to 
prevent from incapable removal in case of rust. 

 

 

 

Troubleshooting: mainly check if the plug connection 
of several wires on the sensor is in good condition, and 
if there is short circuit or open circuit.   
Generally, sensor damage is caused by plumbum and 
phosphorus poisoning, so pay attention to fuel quality, 
meanwhile excessive consumption of engine oil is 
Oxygen sensor has a cable, the other end of which is 
electric connection. The outside of sensor is wrapped 
with asbestos fireproof covering. 

 

There are 4 pins on the joint: 

1# connecting with heating control (ECU1#); 
2# connecting with heating power and main relay; 
3# connecting with sensor ground (ECU36#); 
4# connecting with signal (+) (ECU18#). 
 

 

※  Electronic Control Unit ECU 

Purpose: ECU is the core of electronic engine control 
system. Sensors sent various signals to ECU for 
electric control, and then ECU controls operations of 
fuel injector and ignition coil, etc. after internal 
calculation, thus controlling working of engine. 
 

Normal operation voltage: 9-16V 

Composition:  it has shielded casing and printed 
circuit board, which integrates lots of electronic 
control units for the control of EFI system. 

 

 

氧传感器内部构造图

 

Interior structure of oxygen sensor

ECU 

G-12

Installation:  to be fixed by the support of bracket 
under pilot trench of front windshield. Pay attention to 
waterproofing. 
 

 

Functions:   

Multipoint sequential injection 
Controlling ignition 
Idle speed control 
Independent knocking control on cylinder-by-cylinder 
basis (knock sensor KS-1); 
Providing sensors with power supply: 5V/100mA 
Adopting cylinder-detecting signal (Phase sensor PG1)

λ

closed-loop control with self-adaptation 

Controlling carbon canister control valve 
Air conditioning switch 
Engine-fault indicating lamp 
Fuel quantitative correction 
Engine speed signal output (TN signal) 
Speed signal input 
Failure self-diagnosis with flash code function 
Accepting engine load signal 
 

Troubleshooting: due to the fact that ECU (electric 
control unit) has low failure rate, so generally it is not 
advisable to replace ECU for troubleshooting on any 
problem. Failure of components such as periphery 
circuit and sensors shall be checked and solved firstly. 
Do not replace ECU until all periphery components 
are confirmed to be fault-free. 

 

 

 
Description of pins of ECU: 

Pin 

Connection point 

Type 

Pin 

Connection point 

Type 

1 

Heated oxygen sensor 

Output

42 

A/C temperature sensor 

Input 

2 

Ignition coil 2 

Output

43 

 

 

3 

Ignition ground wire 

Ground

44 

Non-sustained power 

supply 

Input 

4    

45 

Non-sustained power 

supply 

Input 

5 

Ignition coil 1 

Output

46 

Carbon canister Valve 

Output

G-13

6 

Fuel injector 4 (the 2

nd

 

cylinder) 

Output

47 

Fuel injector 3 (the 4

th

 

cylinder) 

Output

7 

Fuel injector 2 (the 3

rd

 

cylinder) 

Output

48    

8 

Output of engine speed 

signal 

Output

49    

9 

 

 

50 

Control of low speed fan  Output

10 

 

 

51 

Electronic ground 2 

Ground

11    

52   

 

12 

Sustained power supply 

Input 

53 

Electronic ground 1 

Ground

13 Ignition 

switch Input 

54 

 

 

14 

The main relay 

Output

55 

 

 

15 

Engine rotary sensor A 

Input 

56 

 

 

16 

Throttle position sensor 

Input 

57 

A/C compressor switch 

Input 

17 

Sensor ground 1 

Ground

58 

 

 

18 

Oxygen sensor 

Input 

59 

Speed signal 

Input 

19 Knock 

sensor 

A Input 

60 

 

 

20 

Knock sensor B 

Input 

61 

Power ground 1 

Ground

22    

63 

Non-sustained power 

supply 

Input 

23    

64 

Phase angle sensor D of 

step motor 

Output

24    

65 

Phase angle sensor A of 

step motor 

Output

25    

66 

Phase angle sensor B of 

step motor 

Output

26    

67 

Phase angle sensor C of 

step motor 

Output

27 

Fuel injector 1 (1 

cylinder) 

Output

68 

Control of high speed fan  Output

28 

 

 

69 

Fuel pump relay 

Output

29 

Inspection light 

Output

70 

A/C compressor relay 

Output

30 

 

 

71 

Diagnostic K wire 

I/O 

31    

72   

 

32 

5V power supply 2 

Output

73 

 

 

33 

5V power supply 1 

Output

74 

 

 

34 

Engine rotary sensor B 

Input 

75 

A/C switch 

Input 

35 

Sensor ground 3 

Ground

76 

Blaster switch 

Input 

36 

Sensor ground connector 

2 

Ground

77 Headlight 

switch Input 

37 

Air intake pressure 

sensor 

Input 78 

 

 

38 

 

 

79 

Phase angle sensor 

Input 

39 

Temperature sensor of 

engine coolant 

Input 80 

Power ground connector 

2 

Ground

40 

Temperature sensor of 

air intake 

Input 81 

 

 

41    

   

 

 

G-14

 

※Electrical fuel pump 

Function:  Supply the fuel from the fuel tank to the 
engine at required pressure and flow (vary from 
individual system). 

 

Structure and working principle: The electrical fuel 
pump is comprised of direct current motor, vane pump 
and end cover (integrated with non-return valve, release 
valve and anti-electromagnetic interference elements). 
The pump and the motor are mounted on the same shaft 
and sealed in the same house. The pump and motor are 
surrounded by the gasoline for cooling and lubrication. 
The battery supplies power to the electrical fuel pump 
through the fuel pump relay and the pump relay 
switches on the circuit of the electrical fuel pump only 
during start-up and operation of the engine. If the 
engine stops running due to malfunction, the fuel pump 
will stop operation automatically. The maximum 
pressure at exit of the electrical fuel pump is 
determined by the release valve within the range of 
450-650 kPa. However the pressure of the whole fuel 
system fluctuates along with fluctuation of the air 
intake manifold pressure. The difference between the 
system pressure and the air intake manifold pressure, 
which normally is 350kPa, is determined by the fuel 
pressure regulator. 

 

Note:  The temperature of fuel has a large impact on 
performance of the fuel pump. When running under 
high temperature for a long time, if the fuel temperature 
is higher than a certain temperature, the pressure of the 
fuel pump will be decreased rapidly. So please check 
carefully whether the performance of the fuel pump 
under high temperature is good if the engine fails to hot 
start. 

 
 

 

Pins: The electrical fuel pump has two pins connecting 
to the fuel pump relay. Beside these 2 pins there are 
marks of “+” and “-” on the shell of the fuel pump 
respectively, which represent the positive and negative 
grid. 
The 70# pin of ECU controls the fuel pump relay. 
 
 
 
 

 

 

Electrical fuel pump 

Circuit diagram of the electrical fuel

 

G-15