Chery A11. Manual - part 174

Maintenance Manual for Chery·Windcloud

M7.9.7 EFI System

4. Knock Sensor KS

Purpose: this sensor is designed to provide
ECU with engine knocking information so
as to carry out knocking control.

Composition and principle: knock sensor
is a sort of vibration acceleration sensor,
which is fixed on engine cylinder block.
ECU controls engine ignition via signals
detected by pressure-sensing element.

Failure diagnosis: ECU monitors on
various sensors, actuators, power
amplification circuits and sensing circuits. In
case any of the following situations occurs,
failure mark of the knock sensor is set.
Knock sensor failure
Knocking control data processing circuit
failure
Cylinder-detecting signal is unreliable
After failure mark of knock sensor being set,
knocking closed-loop control is shut down,
reduceing a safety angle from the ignition
advance angle stored in ECU. When error
frequency cuts down to below setting value,
failure mark restores.

Installation hint: tightening torque is
20±5Nm.

Knock sensor with cable

1. Knocking block
2. Casing

3. Piezoelectric ceramics
4. Contactor
5. Electric connection

Circuit diagram of knock sensor

Pins:
1 Knock sensor signal 1 (ECU19#)
2 Knock sensor signal 2 (ECU20#)

Troubleshooting: mainly check if there is

short circuit or open circuit on the

connection between 2 lines on senosr and

corresponding ECU pins.

If gasket is added during installation; if

tightening torque is proper.
If there is stitching defect between sensor
and cylinder, or there is foreign matter
between them.

Maintenance Manual for Chery·Windcloud

M7.9.7 EFI System

5. Oxygen Sensor
Purpose: this sensor is designed to provide

the information that if there is surplus

oxygen after full combustion of fuel, which

is injected into engine cylinder in the intake

air. ECU, when applying this information,

can carry out fuel quantitative closed-loop

control so as to achieve utmost conversion

and purification of the three major toxic

elements (HC, CO and NO

) in the engine

exhaust with the application of three-way

catalytic converter.
Composition and principle: the sensing

element of oxygen sensor is a porous

ceramic pipe, the outer side of pipe wall is

surrounded by engine exhaust, while inner

side vents to atmosphere. According to

inside and outside oxygen concentration

difference, sensor figures out indirectly fuel

injection pulse width, and then transfers the

information to ECU, and the ECU controls

the injection again.

The working voltage of oxygen sensor

fluctuates between 0.1-0.9V, 5-8 variations

in 10 seconds is required; if lower than such

frequency value, it shows that the sensor is

aged, and needs replacement. The said

sensor is unrepairable.
Failure diagnosis: ECU monitors on

various sensors, actuators, power

amplification circuits and sensing circuits. In

case any of the following situations occurs,

failure mark of the oxygen sensor is set.

Accumulator voltage is unreliable

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

liable to result in sensor failure.

Oxygen sensor

Main relay

Oxygen
sensor

Circuit diagram of oxygen sensor

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#).

Interior structure of oxygen sensor

Maintenance Manual for Chery·Windcloud

M7.9.7 EFI System

6. 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 controling 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.

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

ECU

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.

Maintenance Manual for Chery·Windcloud

M7.9.7 EFI System

3. ECU Pin Definition:

Connected to

Type

Connected to

Type

Oxygen sensor heating

Output

Air conditioning temperature
sensor

Input

Ignition coil 2

Output

3 Ignition

ground

Ground 44 Non-continuous power

Input

45 Non-continuous

power Input

Ignition coil 1

Output

Carbon canister valve

Output

Injection nozzle 4 (Cylinder 2)

Output

Injection nozzle 3 (Cylinder
4)

Output

Injection nozzle 2 (Cylinder 3)

Output

Engine speed signal output

Output

Low speed fan control

Output

Electronic ground 2

Ground

Continuous power

Input

Electronic ground 1

Ground

13 Ignition

switch

Input 54

14 Main

relay

Output

Engine rotational speed sensor A

Input

Throttle position sensor

Input

Air conditioning compressor
switch

Input

Sensor ground 1

Ground 58

Oxygen sensor

Input

Speed signal

Input

19 Knock

sensor

Input 60

Knock sensor B

Input

Power ground 1

Ground

63 Non-continuous

power

Input

Stepper motor Phase D

Output

Stepper motor Phase A

Output

Stepper motor Phase B

Output

Stepper motor Phase C

Output

Injection nozzle 1 (Cylinder 1)

Output

High speed fan control

Output

Fuel pump relay

Output

Inspection lamp

Output

Air conditioning compressor
relay

Output

K wire diagnosis

Input
/output

5V power 2

Output

5V power 1

Output

Engine rotational speed sensor B

Input

Air conditioning switch

Input

Sensor ground 3

Ground 76

Blower switch

Input

Sensor ground 2

Ground 77

Headlight switch

Input

Intake pressure sensor

Input

79 Phase

sensor

Input

Engine coolant temperature sensor Input

Power ground 2

Ground

Intake air temperature sensor

Input

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