Chery A15. Manual - part 30

Troubleshooting: mainly check if there is short circuit 
or open circuit on the connection between 4 lines on 
sensor and ECU.   
If there is short circuit, open circuit or grounding 
between sensor wire harnesses. 

 

 

 

 

 

 

 

Sectional view of intake pressure and 
intake air temperature sensor 

 

1 Seal ring 

5 Casing   

2Stainless steel bushing  6 Pressure bracket 

3 PCB 

7 Welded joint 

4 Sensing element 

8 Bonded joint 

※Throttle Position Sensor   

Purpose: this sensor is designed to provide ECU with 
information of throttle angle. As per such information, 
ECU obtains 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: Consisting of two 
compass sliding contact resistors and two sliding 
contact arms, throttle position sensor is an angle 
sensor that outputs linear signals. The axes of contact 
arms are on the same axial line with throttle axis, with 
5V power supply voltage US being applied to both 
ends of each contact resistor. When throttle turns, 
contact arms turn along with it and move on sliding 
contact resisters, educing potential of contacts UP as 
output voltage. This sensor is actually an angle 
potentiometer. 

 

Failure diagnosis: ECU monitors throttle angle, and 
detects sensor failure when output signal exceeds 
upper or lower limit, in which case engine will work in 
failure mode, and fault indicating lamp will go on. 
 

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

 

 

 

 

Throttle Position Sensor 

Circuit diagram of throttle position sensor 

G-8

Pins: 

1 sensor signal ground (ECU17#) 
2 5V power (ECU32#) 
3 sensor signal (ECU16#) 
 

Troubleshooting: mainly check if there is short circuit 
or open circuit on the connection between 3 lines on 
sensor and ECU.   
Check to see if there is short circuit, open circuit or 
grounding between sensor wire harnesses. 

 

※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 except linear relation. The said 
thermistor is installed in a heat-conducting sleeve. 
ECU monitors water temperature variation by 
converting resistance value of thermistor into a 
changing voltage through a bleeder circuit (inner 
structure of ECU). 

 

 

Failure diagnosis: When coolant temperature is 
higher than allowed upper limit or lower than lower 
limit, failure mark of the knock sensor is set, engine 
fault indicating lamp goes on and engine works in 
failure mode. In this case ECU controls ignition and 
fuel injection according to set water temperature for 
failure mode, at the same time the fan is running at 
high-speed mode. 
 

Limiting data: 2.5±5%KΩ 

Installation hint: tightening torque is 15Nm in 
maximum. 
 

 

Coolant Temperature Sensor 

Circuit diagram of Coolant 

temperature sensor 

G-9

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. 

Pins: this sensor has 3 pins, which can interchange for 
use.   
1 coolant temperature sensor signal (ECU 39#) 
2 sensor signal ground (ECU 35#) 
3 another line connects water temperature signal of 
gauge. 

Troubleshooting: mainly check if there is short circuit 
or open circuit on the connection between 3 lines, 
ECU and gauge on sensor.   
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. 

 

※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, reducing a safety 
angle from the ignition advance angle stored in ECU. 
When error frequency cuts down to below setting 

 

KS with cable 

1.Knocking

block  

2.Casing  

3.Piezoelectric 

ceramics  

4.Contactor  

5.Electric 

connection

Circuit diagram of knock sensor 

G-10

value, failure mark restores. 

Installation hint: tightening torque is 20±5Nm. 

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 
sensor 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. 
 

※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 NOX) 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 

 

Oxygen Sensor

Circuit diagram of Oxygen sensor

G-11