Engine Coolant Temperature 

B

C

A

FE02-5030b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect the engine coolant temperature sensor wiring
harness connector EN23.

(c)

Measure engine coolant temperature sensor resistance.

Standard Resistance (Refer to the specific
parameters

2.2.1.2

 

Temperature Sensor Temperature and

Resistance Correlation

): 2400 Ω (68 ºF) at 20°C

(d)

Connect the engine coolant temperature sensor wiring
harness connector EN23.

Is resistance the specified value?

No

Replace the engine coolant temperature
sensor. Go to step 9

Yes

Step 3

Measure engine coolant temperature sensor signal circuit.

A

C

B

Engine Coolant Temperature Sensor 
Harness Connector EN23

FE02-5031b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect the engine coolant temperature sensor wiring
harness connector EN23.

(c)

Turn the ignition switch to "ON" position.

(d)

Measure voltage between engine coolant temperature
sensor EN23 terminal A and a reliable ground.

Standard Voltage: 4.7-5.5 V

(e)

Connect the engine coolant temperature sensor wiring
harness connector EN23.

Is voltage normal?

No

Go to step 5

Yes

Step 4

Measure engine coolant temperature sensor ground circuit.

A

C

B

Engine Coolant Temperature Sensor 
Harness Connector EN23

FE02-5032b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect the engine coolant temperature sensor wiring
harness connector EN23.

(c)

Turn the ignition switch to "ON" position.

(d)

Measure resistance between engine coolant temperature
sensor wiring harness connector EN23 terminal No.C and a
reliable ground.

Standard Resistance: Less than 3 Ω

(e)

Connect the engine coolant temperature sensor wiring
harness connector EN23.

Is resistance normal?

No

Go to step 6

Engine

Control System JL4G18-D

2-99

Yes

Go to step 7

Step 5

Check the engine coolant temperature sensor signal circuit.

1

3

5

7

8

6

4

2

9

10

11

12

13

23

24

25

26

27

28

29

30

37

51

52

53

54

55

56

57

58

59

60

61

62

63

64

38

39

40

41

42

43

44

45

46

47

48

49

50

31

32

33

34

35

36

14

15

16

17

18

19

20

21

22

ECM Harness Connector EN01

A

C

B

Engine Coolant Temperature Sensor 
Harness Connector EN23

FE02-5033b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect the engine coolant temperature sensor wiring
harness connector EN23.

(c)

Disconnect ECM harness connector EN01.

(d)

Measure resistance between engine coolant temperature
sensor wiring harness connector EN23 terminal A and ECM
harness connector terminal No.41. Check whether the circuit
is open.

(e)

Measure resistance between engine coolant temperature
sensor wiring harness connector EN23 terminal A and a
reliable ground. Check whether the circuit is short to ground.

(f)

Measure voltage between engine coolant temperature
sensor wiring harness connector EN23 terminal A and a
reliable ground. Check whether the circuit is short to power
supply.

Test Items

Standard Value

Resistance Between EN23 (A) and EN01
(41)

Less than 1 Ω

Resistance Between EN23 (A) and a
Reliable Ground

10 kΩ or higher

Voltage Between EN23 (A) and a Reliable
Ground

0 V

Next

Go to step 7

Step 6

Check the engine coolant temperature sensor ground circuit.

2-100

Control System JL4G18-D

Engine

1

3

5

7

8

6

4

2

9

10

11

12

13

23

24

25

26

27

28

29

30

37

51

52

53

54

55

56

57

58

59

60

61

62

63

64

38

39

40

41

42

43

44

45

46

47

48

49

50

31

32

33

34

35

36

14

15

16

17

18

19

20

21

22

ECM Harness Connector EN01

A

C

B

Engine Coolant Temperature Sensor 
Harness Connector EN23

FE02-5034b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect the engine coolant temperature sensor wiring
harness connector EN23.

(c)

Disconnect ECM harness connector EN01.

(d)

Measure resistance between engine coolant temperature
sensor wiring harness connector EN23 terminal C and ECM
harness connector terminal No.40. Check whether the circuit
is open. If there is no open circuit, repair the faulty part.

(e)

Measure voltage between engine coolant temperature
sensor wiring harness connector EN23 terminal C and a
reliable ground. Check whether there is a short circuit. If there
is no short circuit, repair the faulty part.

Test Items

Standard Value

Resistance Between EN23 (C) and EN01
(40)

Less than 1 Ω

Voltage Between EN23 (C) and a Reliable
Ground

0 V

Execute next step as per normal.

Next

Step 7

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 8

Replace ECM.

Next

Step 9

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

Engine

Control System JL4G18-D

2-101

Yes

Step 10

Diagnostic completed.

5. Repair Instructions:

Replace the engine coolant temperature sensor. Refer to 

2.2.8.6

 

Engine Coolant Temperature Sensor Replacement

.

2.2.7.20 DTC P0122 P0123

1. DTC Descriptor:

DTC

P0122

Throttle Position Sensor Circuit Voltage Lower Than Minimum

DTC

P0123

Throttle Position Sensor Circuit Voltage Higher Than Maximum

The actual throttle position will be compared with throttle position determined by the engine load. Engine Control Module (ECM)
detects  the  engine  load  by  intake  manifold  absolute  pressure  sensor  (MAP)  signal.  After  further  comparison,  ECM  determines
whether there is a sensor fault and set the corresponding DTC codes.

•

ECM provides 5 V reference voltage through ECM harness connector EN01 terminal No.39 to TPS sensor harness connector
EN27 terminal No.1.

•

TPS provides sensor signal voltage through EN27 terminal No.3 to ECM harness connector EN01 terminal No.26.

•

ECM provides low reference voltage through ECM harness connector EN01 terminals No.14 and No.18 to TPS sensor harness
connector EN27 terminal No.2.

2. Conditions For Setting DTC and The Fault Location:

DTC Code

DTC Detection

Strategy

Conditions For Setting The DTC (Control

Strategy)

Fault Locations

P0122
P0123

1. Higher Than

Throttle Position
and Angle
Signals Maximum
Limit

2. Lower Than

Throttle Position
and Angle
Signals Minimum
Limit

1. Throttle Position angle signal is greater than

99%.

2. Throttle Position angle signal is less than

1.2%.

3. Engine speed is greater than 800 rpm.

1. Sensor Circuit

2. Sensor

3. ECM

2-102

Control System JL4G18-D

Engine