The vehicle speed signal is used to monitor the vehicle speed. The vehicle speed signal is one of the fuel control reference signals
during an urgent deceleration. The vehicle speed sensor working voltage is provided by The Main Relay which is controlled by ECM
via ECM harness connector EN01 terminal No.57. The vehicle speed sensor signal is sent to the instrument panel used for the
vehicle speed display.

2. Conditions For Setting DTC and The Fault Location:

DTC Code

DTC Detection Strategy

Conditions For Setting The DTC (Control Strategy)

Fault Locations

P0502

Vehicle Speed Sensor No

Signal

1. Under hot operating conditions, driving the vehicle at

Low-Speed at 3rd gear, Disconnect the vehicle
speed sensor. and then press the acceleration pedal
hard to accelerate to higher than 4,000 and
immediately release the pedal. Engine speed,
vehicle speed and MAP values begin to decline.
When entering the fault setting window, DTC code
will be set.

2. Under hot operating conditions, driving the vehicle at

medium speed at 4th gear, Disconnect the vehicle
speed sensor. and then press the acceleration pedal
to accelerate the vehicle. Engine speed, vehicle
speed and MAP values entering the fault setting
window, DTC code will be set.

1. Vehicle Speed Sensor

Circuit

2. Vehicle Speed Sensor

3. ECM

3. Schematic:

MAIN

EF12

5

2

3

1

2

1

3

VSS

MPR

41

62

EO35

EO35

Main Relay

From Battery

Engine 

Control 

Module

Vehicle 

Speed 

Sensor

To Meter

FE02-5292b

Engine

Control System JL4G15-D

2-747

4. Diagnostic Steps:

Step 1

Road test the vehicle. Is the vehicle speed meter display working properly?

(a)

If the instrument panel displays the vehicle speed as per
normal, the vehicle speed sensor is working correctly.

(b)

If the instrument panel displays the vehicle speed
abnormally, the vehicle speed sensor or the circuit may be
faulty.

No

Go to step 3

Yes

Step 2

Check the vehicle speed signal circuit.

1

2

3

1

17

33

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

Vehicle Speed Sensor Harness Connector EO21

ECM Harness Connector EO35

FE02-5293b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect vehicle speed sensor wiring harness connector
EO21.

(c)

Disconnect ECM harness connector EO35.

(d)

Measure resistance between the vehicle speed sensor
harness connector EO21 terminal No.3 and ECM harness
connector EO35 terminal No.41. Check whether the circuit is
open.

(e)

Measure resistance between the vehicle speed sensor
harness connector EO21 terminal No.3 and a reliable ground.
Check whether the circuit is short to ground.

(f)

Measure voltage between the vehicle speed sensor harness
connector EO21 terminal No.3 and power supply. Check
whether the circuit is short to power supply.

Test Items

Standard Value

Resistance Between EO21 (3) and EO35 (41)

Less than 1 Ω

Resistance Between EO21 (3) and A Reliable
Ground

10 kΩ or higher

Voltage Between EO21 (2) and A Reliable
Ground

0 V

Are the values specified values?

No

Repair or replace wiring harness connectors.
Go to step 8

Yes

Go to step 6

Step 3

Check the vehicle speed sensor power supply circuit.

2-748

Control System JL4G15-D

Engine

1

2

3

Vehicle Speed Sensor Harness Connector EO21

FE02-5294b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect vehicle speed sensor wiring harness connector
EO21.

(c)

Turn the ignition switch to "ON" position.

(d)

Measure voltage between vehicle speed sensor harness
connector EO21 terminal No.1 and a reliable ground.

Standard Voltage: 11-14 V

(e)

Connect vehicle speed sensor harness connector EO21.

Is the value specified value?

No

Check whether there is a short circuit between
the vehicle speed sensor terminal No.1 and
the main relay terminal No.87. Repair the
faulty part.

Yes

Step 4

Check the vehicle speed sensor ground circuit.

1

2

3

Vehicle Speed Sensor Harness Connector EO21

FE02-5295b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect vehicle speed sensor wiring harness connector
EO21.

(c)

Measure resistance between vehicle speed sensor harness
connector EO21 terminal No.2 and a reliable ground. Check
whether the circuit is short to ground.

Standard Resistance: Less than 1 Ω

Is the value specified value

No

Check whether there is an open circuit
between the vehicle speed sensor terminal
No.2 and a reliable ground. Repair the faulty
part.

Yes

Step 5

Replace the vehicle speed sensor.

Next

Go to step 8

Step 6

Check ECM power supply circuit.

(a)

Check whether ECM power supply circuit is normal.

(b)

Check whether ECM ground circuit is normal.

No

Repair the faulty part.

Yes

Step 7

Replace ECM.

(a)

Carry out crankshaft self learn after ECM replacement. Refer
to 

2.12.7.11

 

Crankshaft Position Sensor (CKP) Learn

.

Engine

Control System JL4G15-D

2-749

Next

Step 8

Use scan tool to confirm whether the DTC code is stored again.

(a)

Connect scan tool to the datalink connector.

(b)

Turn the ignition switch to "ON" position.

(c)

Clear DTC code.

(d)

Start and run the engine at idle speed to warm up the engine
for at least 5 min.

(e)

Read control system DTC code again to confirm that the
system has no DTC code.

No

Intermittent Fault. Refer to 

2.2.7.3

 

Intermittent

Fault Check

.

Yes

Step 9

Diagnostic completed.

2.12.7.42 DTC P0506 P0507

1. DTC Descriptor:

DTC

P0506

Idle Speed Too Low

DTC

P0507

Idle Speed Too High

Throttle actuator control motor is controlled by the engine control module (ECM). Internal DC motor drives throttle body. In order to
reduce idle speed and adjust the spark and fuel supply, engine control module commands the throttle to close. By reducing the air
flow into the engine, idle speed is lowered. In order to improve idle, the engine control module commands the throttle to open, so
that more air flows through the throttle.

Engine  Control  Module  (ECM)  calculates  and  controls  engine  idle  speed  based  on  coolant  temperature,  speed  compensation,
reducing speed, Air-Conditioning compensation and voltage compensation.

2. Conditions For Setting DTC and The Fault Location:

DTC Code

DTC Detection Strategy

Conditions For Setting The DTC (Control

Strategy)

Fault Locations

P0506

Idle speed is lower than the
target speed by 100 rpm

1. Engine is at idle.

2. Vehicle speed is equal to 0.

3. Engine coolant temperature is higher

than 60°C (140 ºF) .

4. Duration Longer Than 10 s.

1. ETC throttle body assembly

2. Intake System

3. Exhaust System

4. ECM

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Control System JL4G15-D

Engine