Chery S11 / Chery QQ. Manual - part 204

Chery  QQ  Maintenance Manual                          372 EFI System 

 

 

1

 

Chapter 1    The princple for EFI and actuator 

 
1.Intake air pressure and intake 
Temperature sensor 
Usage: Measure baro pressure in manifold and 
intake air temperature to supply laod information 
for engine. 
Constitute and pricinple:The sesor   
Consisits of two sensors, MAP and IAT, which 
mounted on voltage stablizer box. 
MAP: Map consisits of one silicon chip that etched 
a film on the chip. There are 4 piezoelectirc 
resistances that consist of a Wiston bridge. The 
information processing circuit is also on the chip. 
The chip consists of closed reference space with a 
metal shell. The air absolute pressure in the space 
is nearly to zero. 
In this way, a micro electric-mechnic system is 
formed. The active face of the chip is endured a 
pressure nearly to zero, and MAP pressure applies 
on the back of the chip through a connecting pipe. 
The thickness of the chip is only several microns
（　

um），so the change of MAP pressure will 

result the mechanical disform for the chip together 
with 4 resistances to change their resistance. 
The voltage signal that is linearity with pressure is 
formed after processing by information processing 
circuit in the chip. 

Intake air pressure: IAT is a resistor with NTC. 

Like coolant temperature sensor, the resistance 
decreased with the temperature increasing. ECU in 
engine monitors the change of intake air 
temperature (conresponding in series circuit). 
Diagnosis: The open, short or wear of sensor could 
be ditected by the rear electronic unit of MAP. 
ECU will judge the malfunction of sensor if the 
out put signal exceeds the signal outside the curve 
of output feasure. 

 
For examle, if the intake air pressure is higher 

than the up limit or lower than lower limit,ECU   
will judge thar sensor is malfunction ( The intake 
air pressure is below lower limit in starting, but 
ECU can juge sarting condition), “CHECK   
ENGINE”light will on at same time and engine 
will run at malfunction mode. ( The light will not 
on for all malfunctions). 

 

MAP/ IAT 

进气压力温度传感器

 

The circuit for MAR/IAT 

MAR/IAT

 

Pins: No.1 Ground 
No.2 Output signal of temperature 
No.3 To 5V 
No.4 Output pressure signal 

 

 

Chery  QQ  Maintenance Manual                          372 EFI System 

 

 

 

2

 

The section plane of MAP/IAT 
1.Seal 2. Stainless steel bush 3. PCB plate 4. 
Sensor    5. Shell6. Support 7. Welding conncetion 
8. Felt connection 
 
2. TPS 
Usage: TPS is used to supply Throttle angle signal. 
According to this signal, ECU will receive enging 
load signal and working condition signal such as 
starting, idle, back up, partial load, and full load) 
as well as acceleration and decelation signal. 
Consititue and pricinple:TPS is a angle sensor with 
linear output. It consists of 2 arc slide resistors and 
2 slide arms. The shaft of arm and throttle shaft 
connect to one axes. When running throttle, arm 
run together and slides on resistor. Putout UP as 
output voltage. 
So it is a angle potetiameter. ECU use UP/US as 
ratio to vioid the fluctuate of sensor value caused 
by engine voltage fluctuate.   
Diagnosis: ECU check if throttle angle exceeds 
the up limit or lower Limit of output signal. If so, 
ECU will judge TPS malfunction, engine will run 
at malfunction mode, MIL will on( Knock sensor 
or dirty will cause engine malfunction). 
Install: Screw torque for bolts: 1.5Nm-2.5Nm   

 

Out view of TPS 

Pins:1. Volt output  2. Signal ground  3. Signal 

output 
 

节气门位置传感器

   

TPS 

Diagram of TPS 

3. ECT TF-W 
Usage: ECT is used to supply Coolant temerature 
information for the timing and fuel inject pulse 
width control on engine start, idle, normal running. 
Constitue and pricinple: ECT is a termal sensive 
resistor with ntc. The resistance decreases with 
coolant temperature increase, but it is nor linrearity. 
The resistor is enclosed in copper bush. The 
change of resistance is transformed into changing 
voltage to ECU by a voltage distribute circuit to 
monitor the change of water temperature. 
Diagnosis: When coolant temperature is over up 
limit, or below lower limit, MIL is on, engine run 
at malfunction mode. ECU control ignition and 
fuel inject according to set temperature. Fan runs 
at high speed. 
Limit data: 2.5±5%KΩ 
Hint: Screw torque: 15±2Nm 
Hint: There are 2 sensors in vehicle. One is single 
pin water temperature and supply water 
temperature signal for water temp meter; The other 
is double pins and supply the temp signal to ECU. 
 

Chery  QQ  Maintenance Manual                          372 EFI System 

 

 

3

 
 
 

 

Diagram of ECT 

Pins: There are 3 pins which could be 
interexchangable. 
a.  EFI water temperature signal pin, resistance 

is 2.45KΩ at 200C. 

b.  Instrument water temperature signal pin, 

resistance is 0.05KΩ at 800C. 

c. Signal 

ground 

接仪表

b

                Circuit diagram of ECT 
Hint: There are 1 water temperature sensor with 3 
lines on it. One is ower line, two are signal lines 
which one to ECU and the other to instrument.   
 
4. KS 
Usage: Supply knock signal to ECU for knock 
control. 
Consititution and principle: 
KS is vibration accelaration sensor mounted   

 
 
onengine. The sense element is a piezoelectricity 
element. The vibration of cylinder is transformed 
to piezoelectrical crystal through mass block in   
 
sensor. The pressure of crystal produce voltage on 
two polar faces and change vibration signal into 
output AC voltage signal. 
Because the frequency of vibration caused by 
engine knock is much higher than normal 
frequency of engine vibration signal, so ECU can 
distingquish knock and unknock signals after 
filtering the signal of KS. When engine load, speed 
and coolant temperature exceed gate value, and not 
set KS malfunction information record, the signal 
of KS will be used to close loop control for 
knocking. When the control is actuated, the signal 
of KS will input to ECU for integral after amplify 
and filter. 
When certain integral value in crank angle exceeds 
gate value, ECU will consider the knock happens, 
and reduce 1 degree of ignitionadvanced-angle. If 
knock happens on next cycle, ECU will reduce 1 
degree of ignitionadvanced-angle again; If no 
knocks happen in next cycles, ECU will resume 
the angle to normal value. 
Diagnosis: ECU monitors each sensor, actuator, 
power amplifier and check circuit. KS will mark 
malfunction position once following situations 
happen: 

KS malfunction 
KS control data process circuit malfunction 
Cyinder identification signal is untrustable 

After KS marks the malfunction position, knock 
close loop control will shut off and reduce 1 safty 
degree for ignition advanced-angle stored in ECU. 
When wrong frenquency is below set value, 
malfunction position will resume. 
Hint: Screw torque 20± 5Nm

　

. 

 
 
 

 

Chery  QQ  Maintenance Manual                          372 EFI System 

 

 

 

4

 

KS with cable 

爆震传感器

 

The diagram of KS 

 
Pins: pin 1 and pin 2 connect ECU 
The shield wire of sensor is folded on outside of 
signal wire. 
 
 
 
 
 
 

 
 
5. Oxygen sensor 
Usage: The sensor is used to supply the 
information that if oxygen is superfluous after the 
fuel in cylinder combused completely in intake 
air.ECU    uses the information to close-loop 
control for quantitative fuel and transforms or 
purifies three venomousnee ingredients such as HC, 
CO and NOX in catalyzer. 

Constitue and priciple: The sense element is a 

ceramic pipe with bores. The outside of pipe is 
surrounded by exhaust of engine, and inside is 
touched with automosphere. The pipe wall is one 
kind of solid electrolyte with electric heating pipe 
in it to heat ceramic body    to 300 Cº for ceramic 
body to work.The oxygen ion can pass pipe freely.     

The concentration diffrencial is transformed 

into electric differencial with this feature to form 
electric signal. If mix air is richer, electric 
differencial and output voltage are higher; if mix 
air is leaner, electric diferencial and output voltage 
are lower.   

The working voltage of sensor fluctuates 

between 0.1-0.9V with 5-8 times every 10 seconds. 
Sensor is aging if the frequency is below this value 
and needs replacing. The sensor cannot be 
repaired.   
  Disgnosis: ECU monitors each sensor, actuator,   
power amplifier and check circuit. ECU will mark 
the malfunction position for oxygen sensor once 
one of following situations happen: 
    Battery voltage is not trustable. 
    MAP signal is not trustable. 
    Injector driver is fault. 
    After marking malfunction position for oxygen 
sensor, fuel ration close-loop control will shut off 
and will be carry on according to basic inject time 
stored in ECU.   
  Install hint: The screw torque of sensor is 
50-60Nm. Smear anti-corsion oil on sensor after 
replacing.