Chery QQ6 (S21) / S12LHD. Manual — part 98

11.4 Front Oxygen Sensor Failure . . . . . . . . . . . . . . . . . . . . . ..38

11.5 Rear Oxygen Sensor Failure . . . . . . . . . . . . . . . . . . . . . ...40

11.6. Coolant Temperature Sensor Failure . . . . . . . . . . . . . . . . . . .42

11.7 Failure in Driver Stage of Injector . . . . . . . . . . . . . . . . . . . ..43

11.8 Failure in Driver Stage of Canister Control Valve. . . . . . . . . . . . . ..44

11.9 Failure in Driver Stage of Malfunction Indicator Lamp (MIL) . . . . . . . . ..45

11.10 Failure in Driver Stage of 1#, 2# Coils of Step Motor . . . . . . . . . . . ..46

11.11 Craftshaft Position Sensor Failure . . . . . . . . . . . . . . . . . . . 47

11.12 Craftshaft Position Sensor Failure . . . . . . . . . . . . . . . . . . . 48

11.12 Ignition Coil Failure. . . . . . . . . . . . . . . . . . . . . . . . ..49

11.13 Accelerator Pedal Position Sensor Failure. . . . . . . . . . . . . . . . 50

11.14 Double Brake Swtich . . . . . . . . . . . . . . . . . . . . . . . . 51

11.15 Theft-proof Control System Failure. . . . . . . . . . . . . . . . . . ..52

12. Steps for Implementation of Failure Diagnosis by Engine Symptom. . . . . . . . ...53

12.1 Perform Preliminary Inspection First before Following the Steps for Implementation

of Failure Diagnosis by Engine Symptom. . . . . . . . . . . . . . . . . . . .53

12.2 The Engine Does not Rotate or Rotates Slowly when Starting. . . . . . . . ...55

12.3 When Starting, Engine Can be Dragged to Rotate but Can not Start with Success. ...56

12.4 Warm Starting Difficulty . . . . . . . . . . . . . . . . . . . . . . . 58

12.5 Engine Speed is Normal, but it is Difficult to Start at any Time. . . . . . . . ...60

12.6 Cold Starting Difficulty . . . . . . . . . . . . . . . . . . . . . . . ..62

12.7 Unsteady Idle Speed at Any Time . . . . . . . . . . . . . . . . . . . ..64

12.8 Unsteady Idle Speed during Warming up Process . . . . . . . . . . . . . ..66

12.9. Unsteady Idle Speed after Warming up . . . . . . . . . . . . . . . . . .67

12.10 Unsteady Idle Speed or Extinguish with Load (A/C etc.). . . . . . . . . . .69

12.11 Periodic Unsteadiness (Have to Perform Self-study again after ECU is Power off) 70

12.12 Too High Idle Speed (Have to Perform Self-study again after ECU is Power off) ..72

12.13. Engine Revolution Speed is too Low or Flameout . . . . . . . . . . . . ..73

12.14 Slow Response when Accelerating . . . . . . . . . . . . . . . . . . ...75

12.15 Poor Performance and Disability when Accelerating. . . . . . . . . . . . ..77

12.16 Unable to Reach the Maximum Revolution when Accelerating. . . . . . . ...79

12.17 When Releasing Accelerator Pedal after Acceleration, Unsteady Idle Speed Occurs

at Instant, even Extinguishes. . . . . . . . . . . . . . . . . . . . . . . ...81

12.18 A/C System Failure. . . . . . . . . . . . . . . . . . . . . . . . ...83

13. Safety Precautions for System Maintenance. . . . . . . . . . . . . . . . . . .84

13.1 Safety Precautions for Diagnosis and Maintenance of Gasoline Injection Electronic

Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...84

Chapter One Disassembly and Installation of Electronic Fuel

Injection System

I. Disassembly and Installation of Components of Electronic Fuel

Injection System

1. Disassembly and installation of engine control unit (ECU).

2. Position and disassembly of intake air pressure sensor.

3. Position and disassembly of camshaft position sensor.

4. Remove fixing hoop of intake hose.

5. Remove the four fixing bolts of electronic throttle body.

Pull out the connector and take out the electronic throttle body.

6. Use a screwdriver to press down the fixed clip of the injection

nozzle connector and then pull out the connector.

7. Use a screwdriver to press down the fixed clip of the knock

sensor connector and then pull out the connector.

8. The water temperature sensor is behind the thermostat seat.

9. Pull out the connector of the ignition primary coil by hand.

10. Pull out the connector of the engine tachogenerator by hand.

Chapter Two Principle of Electronic Fuel Injection System

I. Overhaul of System Components

1. Intake Air Temperature Pressure Sensor

1.1 Function of the sensor:

Detect air intake pressure and temperature in air intake manifold, which will be provided to

ECU as main load signal of engine; ECU will calculate injection pulse-width based on this signal.

1.2 Principle of the sensor:

Intake air temperature pressure sensor is a sensor that integrates an intake air pressure sensor

and an intake air temperature sensor. Absolute pressure sensor element of intake manifold is

composed of a silicon chip. A pressure diaphragm is etched on the silicon chip. On the pressure

diaphragm, there are 4 piezo-resistances, which serve as strain sensors and constitute a Wheatstone

bridge. In addition to this pressure diaphragm, a signal processing circuit is also integrated on the

silicon chip. The silicon chip and a metal housing constitute a closed reference, where the absolute

pressure of the gas inside approaches to zero. Thus, a micro-electronic mechanical system is

formed. The active face of the silicon chip stands a pressure close to zero, while its back face stands

the pending measuring intake manifold absolute pressure introduced by a connecting pipe. The

thickness of the silicon chip is merely several

µ

m, so the absolute pressure change in intake manifold

will bring mechanical deformation to the silicon chip. The 4 piezo-resistances will accordingly

deform and their resistances also change. The voltage signal in linear relation to the pressure is

formed after process by the signal processing circuit on the silicon chip. The intake temperature

sensor element is a negative temperature coefficient (NTC) resistance, which will change with the

intake temperature. This sensor sends out a voltage indicating the intake temperature change to the

controller.

Cross-section view for sensor of air absolute pressure and temperature in intake manifold

1 Gasket 2 Stainless Steel Sleeve 3 PCB Board 4 Sensing Element 5 Housing 6 Pressure Bracket 7 Soldering 8

Bonded With Bonding Agent

进气压力温度传感
器

Intake air temperature

pressure sensor