Chery A11. Manual — part 168

Maintenance Manual for Chery·Windcloud

MOTOROLA EFI System

2. Throttle Position Sensor

Purpose: MOTOROLA TPS sensor is
designed to provide ECU with information of
throttle angle and angle rate. As per such
information，ECU could obtain engine load
information and operating mode information
(for instance: start-up, idle speed, reverse, part
load and full load) as well as acceleration and
deceleration information. This sensor is
three-wire style, and the throttle opening can be
detected by ECU via monitoring voltage
variation.




Composition and principle: the said sensor’s
structure is of sliding resistance slice style,
ECU obtains throttle opening signal by
monitoring voltage at the signal output terminal
via comparison circuit inside computer.
Voltage signal is not received directly inside
ECU, instead, output/input signal ratio is tested,
thus preventing from signal fluctuation due to
voltage fluctuation.

2

Failure diagnosis:
Throttle position sensor signal above measuring
range;

Throttle position sensor signal below
measuring range;
Throttle position sensor signal line short
circuit;
Throttle position sensor signal line short
circuit;

Installation: allowable tightening torque
for fastening screw is 1.5Nm-2.5Nm.

Throttle position sensor

（2 refers to throttle position sensor）

Throttle position sensor

Circuit diagram of throttle position sensor

Pins:

1 sensor signal ground (ECU B17#)

2 5Vpower source (ECU B32#)

3 sensor signal (ECU B16#)

Troubleshooting: mainly check if there is

short circuit or open circuit on the connection

between 3 lines on senosr and ECU.

If there is short circuit, open circuit or

grounding between sensor wire harnesses.

Check between sensor signal terminal and

ground wire with multimeter when swtiching

on/off throttle to see if pulse occurs.

Maintenance Manual for Chery·Windcloud

MOTOROLA EFI System

3

3. Coolant Temperature Sensor TF-W

Purpose: this sensor is designed to provide
coolant temperature information. To provide
engine ECU with water temperature signal used
for control of ignition timing and fuel injection
pulse width in startup, idle speed and normal
operation.

Composition and principle: this sensor is a
thermistor of negative temperature coefficient
(NTC) with resistance value decreasing with
the increasing of coolant temperature and vice
versa except linear relation. ECU monitors
water temperature variation as per sensor
output signal and via comparison circuit inside.



Failure diagnosis: water temperature signal
above limit value;
Water temperature signal below limit value;
Short circuit or open circuit occurs in water
temperature sensor line.


Limiting data: 2.5±5%KΩ


Installation hint: tightening torque is 15Nm in
maximum.

Hints: the vehicle is equipped with 2 water
temperature sensors, one is single-pin water
temperature sensor, providing the water
temperature gauge with water temperature
signal; the other is double-pin, providing the
engine ECU with water temperature signal.

Coolant temperature sensor

Water temperature sensor

Circuit diagram of coolant temperature sensor

Pins: this sensor has 3 pins, which can

interchange for use.

1 coolant temperature sensor signal (ECU

B10#)

2 sensor signal ground (ECU B23#)

Troubleshooting: mainly check if there is

short circuit or open circuit on the connection

between 3 lines on senosr and ECU as well as

instrument.

If there is short circuit, open circuit or

grounding between sensor wire harnesses.

Line grounding or defect grounding is liable

to cause engine water temperature gauge to

indicate excessive temperature.

Maintenance Manual for Chery·Windcloud

MOTOROLA EFI System

4

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 judges the
occurrence of engine knocking by using
vibration frequency signal outputed by knock
sensor, which goes through filtration.


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.

1. Knocking block
2. Casing

3. Piezoelectric ceramics
4. Contactor
5. Electric connection

Knock sensor with cable

Knock sensor

Circuit diagram of knock sensor

Pins:

1 Knock sensor signal 1(ECU B2#)

2

Knock sensor signal 2 (ECU B3#)

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 if there is foreign matter between

them.

Maintenance Manual for Chery·Windcloud

MOTOROLA EFI System

5

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

X

) in the engine exhaust with the application

of three-way catalytic converter.
Composition and principle: 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 the fuel injection pulse width, and

transfer 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.

The variation frequency of oxygen sensor

shall not be lower than a certain value within

a specified time.

Oxygen sensor

Main
power

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 power supply and

main relay;

2# connecting with heating control (ECU B16);

3# connecting with sensor signal anode (ECU

B1#);

4# connecting with sensor signal cathode (ECU

B23#).

Interior structure of oxygen sensor