Chery Fora (Elara A520). Manual — part 187

（1）

Fault descriptio n:

Fault analysis：

Troubleshoot

:

Badness idle speed, badness acceleration, badness tail gas, over fuel

consume etc.

Moisture enterin g inside of sensor, then the temperature is ch anged and the pin is broken;

the sensor is poisoned（ Pb,S,Br,Si）

Disassemble joint， Put digital multimeter to ohm shift, connect meter pen to No.1

（white）and No.2（white） pins of the sensor. Normally the resistance value is 1~6Ω.

（2） Connect the joint and keep it at idle speed status. When the oxygen sensor reaches to

its working temperature 350℃, keep digital multimeter to DC volt shift and connect meter pen to
No.3 （gray） and No.4（ black） pins of sensor. Now the voltage should be fluctuate between
0.1- 0.9V quickly （the data also can be gotten from data flow inspected by diagnosis meter）.

ECU

1

2

3

59

T he 1st pin of the vehicle speed s ensor connect t o power
T he 2nd pin conn ect to ground
T he 3rd pin is the vehicle speed s ignal, it connec t to the
59 th pin of engine ECU.

60

75

Br/B

V/W

2

3

4

1

High/Low

pressure Switch

To The

Air Conditioner

Module B19 (AC Switch)

ECU

（8）Vehicle speed sensor

Figure9-12 Ve hicle spee d sensor and its circ uit

（9）A/C pressure switch

Figure9-13 A/C pressure switch and its ci rcuit

（10）Clutch pedal switch

74

Sb/B

ECU/A1/7

Clutch

Pedal

Switch

ECU

The 1st pin of clutch pedal swit ch is connectted
to the 74 th pin of ECU, and the other pin is
connect ted to ground.

Figure9-14 Clutch pedal switch and its circuit

（11） Power steering switch

The 1st pin of the power steering
switch is connectted to the 76th
pin of engine ECU, and the
other pin is connectted to ground.

Figure9-15 Power Steering switch and its circuit

Vehicl e speed sensor

To fuse FB5

Vehicle speed sensor

A/ C high/low pressure

switch

In stallation position of
power steering switch

Clutch pedal switch

The 2nd pin of A/C high/l ow pressure switch connect to the 75th pin of ECU; the 3rd pin conne ct to the
60th pin of ECU; the 1st 4th pin connect to the B19 switch of A/C module.

、

18

76

L

Power

Steering Switch

E CU

Idle speed is not wel l、 accel erate not well、 can not st art

(start difficult)and etc.

Because of th e lackness of maintainen ce, there is coll oid

accumulate in the fuel injector and result in the i nvalidati on.

（ Remove the plug） set the multimeter at the ohm p osition, the

two pens connect to the two pin s of fuel injector, the rating resistance is 12Ω when it is
20℃.

clean the fuel injector with specialized clean analyzer.

Fault d escription

Troubleshoot

：

Fault analysis：

:

Advice：

P ins: each f uel injector has two p ins . The o ne which is marked w ith "+" at one side o f the shell
c onnects to the 87th pin of main relay output port; the o ther conne cts to the 2 7th 6th

7th 47th

p in of ECU.

、

、

、

ECU sends electric impulse to the coil of injec tor and forms the magnetic field

power.Wh en the power incre ases enough to overcome the combined force o f release spring
pressure 、needle v alve grav ity and friction, the needle va lve begin to rise and the fuel inject
procedure start. Wh en the fu el injection impulse stops, the pressure of relea se spring closes
the needle valve again.

can not start.

The current is too h igh to burn 、damage by ou tside force.

It is forbidden to try the "short circuit test way" to test the ignition function, so as

to avoid the damage to electric controller.

（ Remove the plug） set the multimeter at th e OHM position, connecti ng two

pens to the two p ins of primary win ding resp ectively. When it is 20℃, the resistance is
0.42-0.58Ω，and the secondary winding i s 11.2-14 .8kΩ. Refer to table 20℃

Fault description

Troubleshoot

：

Fault analysis ：
Maintain notice：

:

Br

2

2

2

2

G

L

O

47

7

6

27

ECU

Connects to 87#
of main relay

（1）Ignition coil

The ign ition coil transforms the low pressu re DC of battery to the high pressure

electricity, which gets through the spark plug and brings out spark to burn the mixture
in th e cylinder.

F igure9-16 Ignition coil

（2）Fuel injector

Figure9 -17 Fue l injecto r and its circuit

F uel injector

Th e1st coil prim ary windin g is connect ted

to the 5th pin of ECU

The 4th pin is em pty.

The 3rd pi n is connectted to the anode of

pow er

The 2nd coil primary winding is

connectted to the 2nd pin of ECU.

Ig nition coil

V

Ω

kΩ
mH

H

kV
kV

0.58
14.8

4.8

37.5

14

0.5

13.0

4.1

32.0

0.4 2
11. 2

3.4

26. 5

30
23

Elementary winding

Load 50pF

Load50p F//1MΩ

（20-25℃）

（20-25℃）

Min

Ma x

Unit

Primary winding

Seco ndary winding

Resistance

Volta ge

Electromagnetic induction

Model

Cost

C apacity

Elementary winding

Seco ndary winding

Table 2

◆

Actuator

19

The A/C switch open, blower switch open , the A/C pressure is normal, the

evaporator temperature sensor detects the correct data, the A/C requirement signal is
sent to ECU via these switches. After receiving the signal, ECU controls the A/C relay
to close and sends the speed increasing signal to the stepper motor at the same time,
and start the electric fan, then the A/C system will start working.

The battery supplies power to electric fuel pump through fuel pump relay, the relay

can only p ut through the electric fuel pump circuit when startin g or the engine is run ning.
When the engine stop running accidently, the fuel pu mp will also stop automatically.

M

V

70

86

30

85

87

FB16

15A

Fuel Pump

Relay

ECU

Loud noise when running、 can not well accelerate、can not

start（start difficult） and etc.

For t he using of bad fuel
1．Colloid accumulate and form insulated surface
2．fuel pump b ushing and armature locked
3．fuel sensor unit erode.

（ Remove the pl ug） set th e multimeter at the ohm position,

connectin g the two pens to the two pins of fuel pump, test the inner resistance, it is not 0
or（that's to say it is not short circuit or op en circuit state）.

（Connect the plug）connect the fuel pressure gauge at th e oil intak e pipe, start the

engine, ch eck whether the fuel pump work; if it is not work, check the “ +”pin t o see
whether th ere is power voltage; if it works, observe the working conditions of engine to see
whether th e fuel pressure is about 300kPa.

:

Fault description

Trou bleshoot

：

Fault analysis：

：

（ ）Fuel pump relay

3

Figure9-18 Fuel p ump relay circuit di agram

（4）A/C relay

69

ECU

1． The blower mot or fault （ fuse burnt, relay circuit open circuit or short

circuit ）

2．The A/C pressure is abnormal （high pressure is too high and low pressure

is too low） the evaporator temperatu re sensor fault

3．A/C relay line fault （short circuit to ground、short circuit to power、open

circuit）

Common troubles：

Figure9-1 9 A/C relay

To power

To m ain relay

Front engine com partment box

Fuel pump

To main relay To main pow er

Electromagnetic clutch

A /C compres sor

20

A/C relay

The fuel pressure is too low or too high, and start difficultly.

Because lacking of maintenance for a long time, it results in that:

1 The filter screen

jammed ;

2

Grain impurity result in the serious leakage;

3 Manmade mechanical

damage and so on.

（1）It is forbidden to impact the diaphragm with high

pressure gas; （2）It is forbidden to clean it with causticity fluid; （3） It is forbidden to force
on it and result in distortion.

Connect the fuel pressure gauge at the oil intake pipe and start the engine to let it work on

idle speed, check whether the fuel pressure is about 350kPa; step the accelerate pedal until
the engine reaches the speed of 2500rpm, check whether the fuel pressure is about 350kPa
then.

（ ）

（ ）

（ ）

In the maintain procedure:

Fault description

Troubleshoot

：

Fault analysis：

Notice for maintenance：

：

The carbon canister only has two pins,

with one connecting to the 87th p in of main
electric equipment output port , and the othe r
connecting to the 5th pin of ECU.

Canister purge valve controls the volume of cleaning air flow from charcoal

canister to air int ake main pipe. Th e adsorb ing capab ility of carbon canister is l imited,
if the oil steam ad sorbed in the carb on canister can't be consumpt, the oil will volatilize
to outside and pollute the air.

（5）Cooling fan control module

ECU Controls the running of fan according to the engin e coolan t temperature

and A/C requirement signal, it controls the relay of fan system if conditions are met.

Figure8-2 0 Cooling fan control module circ uit

1．High speed relay line is short circui t to power；
2．High speed relay line is short circui t to groun d；
3．High speed relay line is op en circuit；
4．Low speed relay li ne is short circuit to power；
5．Low speed relay li ne is short circuit to ground；
6．Low speed relay li ne is open circuit；
7．Engine coolant temperature sensor f ault；
8．Engine air intake temperat ure sensor fault；

Common troubles：

（6）Canister purge valve

46

ECU

Figure8-2 1 Canister purge valveand its circuit

To main relay

M

M

86

30

85

87

A6

A5

86

30

85

87

B/O

W

68

50

High electrical

fan relay

FrontGround/

DC/2

ECU

Fan control

m odule

To Ground

To Main Re lay To Main Power

21

Low electrical

fan relay

Canister pu ge valve

r

Canister purge valve