Chery Tiggo T11 LHD. Manual — part 48

Chery T11 Service Manual Electric Injection System

5

3. Coolant Temperature Sensor (THW, CTS)

Application: This sensor is used to provide the

information about the coolant’s temperature. It

can offer an engine’s ECU the water

temperature signal which is available to control

the startup, idle, ignition timing during the

normal operation, and fuel injection pulse width.

At the same time, it also offers instruments the

water temperature signal which is applied for

the

water

temperature

display

of

the

instruments. The water temperature signal is the

most signal for the cold start of the engine.

During the period of cold start, the fuel

injection quantity depends on the signal proved

by the water temperature sensor.

Structure and Principle: This sensor is a

thermistor with negative temperature coefficient

(NTC), whose resistance reduces as the coolant

temperature rises, and increases as the coolant

temperature drops, but it isn’t linear. Based on

the output signal from the sensor, the ECU

monitors the change of water temperature

through its internal comparison circuit.

Trouble Diagnosis:

1) The water temperature signal is higher than

the limit value;

2) The water temperature signal is lower than

the limit value;

3) The open or short circuits of the water

temperature sensor.

Resistance value data at normal temperature:

2.5±5%KΩ

Installation Hint: The max. tightening torque is

20 Nm.

Hint: This vehicle is equipped with the

three-wire water temperature sensor. This kind

of sensor features with the cost-effective and the

system consistency.

Profile of a coolant temperature sensor

T11 Water Temperature Sensor

Circuit diagram of coolant temperature sensor

Pin:

This sensor has three pins in total, which can be

exchanged each other.

1) No1 (A) for the sensor grounding wire (to

Ecu 5#);

2) No 2 (B) for the water temperature sensor

signal wire (to ECU 43#);

3) No 2 (C) for the water temperature gauge of

the instruments;

To instrument

Chery T11 Service Manual Electric Injection System

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The three wires of the sensor are respectively:

a. The 5V standard power supply wire;

b. The sensor signal wire (for ECU);

c. The

sensor

signal

wire

(for

instruments).

Troubleshooting:

1) Mainly examine the short or open circuit

between the three wires on sensor and the

ECU or instruments.

2) Examine the short or open circuit and the

grounding among the harnesses of sensor.

3) Examine the bad wire earth or earth, which

easily cause the over-high temperature

indicated on the water temperature gauge of

the engine.

Characteristic Parameters (Standard Value):

-10℃

16120Ω

0℃

9399Ω

20℃

3511Ω

60℃

671Ω

90℃

241Ω

Operating Voltage: 5V DC

Opening Temperature Range: -40 ℃ to

135℃

4. Knock Sensor (KS, KNK)

Application: This sensor is used to provide the

ECU with the knock information of the engine to

conduct the knock control.

Structure and Principle: The knock sensor is a

kind of vibration acceleration sensor mounted on

the cylinder body of an engine. It is generally

installed between the No 2 cylinder and the No 3

cylinder, which is in favor of the knock balance of

the engine. The ECU utilizes the vibration

frequency signal output from the knock sensor to

determine the knock of the engine through the

wave filtering inside the ECU. When the knock

signal is detected, the ECU will gradually reduce

the knock till there is no knock, and then gradually

resume the knock till up to the upper limit of

knock. Repeat this procedure above.

Profile of a knock sensor with cable

Chery T11 Service Manual Electric Injection System

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Trouble Diagnosis: The ECU monitors the

knock sensor, power amplification circuit and

testing circuit. The fault flag of the knock

sensor will be set if one of the following

conditions occurs:

1) The knock sensor fails;

2) The knock control data processing circuit

fails;

3) There are some insincere cylinder detection

signals;

4) The sensor wire fails.

After the fault flag of the knock sensor is set,

the closed-loop control for knocking closes and

then the ignition advance angle stored in the

ECU is identified as a safety angle by the

software program. The fault flag resets when

the error frequency drops down to the setting

value below.

Installation Hint: The tightening torque is 20
±5Nm.

Troubleshooting:

1) Mainly examine the short or open circuit

between these two wires on sensor and the

corresponding ECU pins.

2) Examine the installation torque of sensor

and whether the gaskets are added when

the sensor is installed.

3) Examine the bad press fit between the

sensor and the cylinder body, or the foreign

material between the sensor and the

cylinder body.

T11 Knock Sensor

Circuit diagram of the knock sensor

Pin:

1) No 1 (A) for the knock sensor signal 1 (to

ECU 5#)

2) No 2 (B) for the knock sensor signal 2 (to

ECU 69#)

Operating temperature range: -40 ℃ to

150℃

Resistance value: > 1MΩ

Chery T11 Service Manual Electric Injection System

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5. Oxygen Sensor (O

2

S)

Application: This sensor is used to provide the

information about weather the oxygen is

superfluous after the fuel injected into the

engine cylinder fully combust together with air

intake. Based on these information, the ECU

can conduct the fuel quantitative closed-loop

control to convert and purify three main toxic

components, i.e. HC, CO and Nox which exist

in the engine exhaust, with the help of

three-way catalytic converter.

Structure and Principle: The sensing element

of the oxygen sensor is a kind of ceramic tube

with small holes, which the outside of tube wall

is surrounded by the engine exhaust while the

inside is full of air. Based on the oxygen

concentration difference between the inside and

the outside, the sensor indirectly figure out the

pulse width of the fuel injection, transmit the

width to the ECU, and then the ECU controls

the fuel injection again. At the same time, The

output data from the rear oxygen sensor are

detected, and, in the ECU, the data from the

front and rear oxygen sensors are compared to

monitor the operation of three-way catalytic

converter.

The operating voltage of the oxygen sensor

fluctuates at the range of 0.1 to 0.9 V, and

changes 5 to 8 times every 10 seconds. If the

change frequency is less than this specified

frequency, it indicates that the sensor is aged

which needs to replace. This sensor is difficult

to repair.

Trouble Diagnosis:

The ECU detects the oxygen sensor, wires and

the power amplification circuit and testing

circuit inside ECU. The fault flag of oxygen

sensor will be set if one of the following

conditions occurs:

Profile of a oxygen sensor

T11 Oxygen Sensor

Circuit diagram of front oxygen sensor

All front oxygen sensors have the cables. The

other end of a cable is the electrical connection.

There is a layer of asbestos fireproof covering

around the outside of the sensor

Main Relay