It is prohibited directly contact the ignition wire with the ground, as this may damage the ignition coil or the engine
control module. the correct approach is to use a good spark plug with one end to connect the ignition wire, the other
to a reliable ground.

Step 1

Are instruments, wiper and other electrical accessories working properly?

No

Ignition relay IG1 is not working properly.
Refer to 

2.10.7.4

 

Ignition Relay IG1 No Power

Output

Yes

Step 2

Check the ignition coil power supply.

Ignition Coil Harness Connector EN19 (EN20)

1

2

FE02-9006b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect the ignition coil harness connector EN19 (EN20).

(c)

Turn the ignition switch to "ON" position.

(d)

Measure the voltage between ignition coil harness connector
EN19 (EN20) terminal No.1 and a reliable ground.
Standard Voltage: 11-14 V
Is the voltage specified value?

No

The ignition relay IG1 terminal No.30 circuit is
open.

Yes

Step 3

Measure the ignition coil primary resistance.

Ignition Coil

FE02-9007b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect the ignition coil harness connector EN19 (EN20).

(c)

Measure resistance between the ignition coil terminal No.1
and No.2.
Standard Resistance Value: 0.7-0.9 Ω
Is the resistance specified value?

No

Replace the ignition coil. Refer to

2.10.8.3

 

Ignition Coil Replacement

Yes

Step 4

Measure the ignition coil secondary resistance.

Engine

Ignition System JL4G18-D

2-527

Resistance

FE02-9008b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect the ignition coil harness connector EN19 (EN20).

(c)

Measure resistance between the ignition coil secondary
terminals.
Standard Resistance Value: 9.68-12.32 kΩ
Is the resistance specified value?

No

Replace the ignition coil. Refer to

2.10.8.3

 

Ignition Coil Replacement

Yes

Step 5

Check the ignition coil control 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

Ignition Coil Harness Connector EN19 (EN20)

1

2

FE02-9009b

(a)

Turn the ignition switch to "OFF" position.

(b)

Disconnect ECM harness connector EN01.

(c)

Disconnect the ignition coil harness connector EN19 (EN20).

(d)

Measure resistance between ECM harness connector EN01
terminal No.3(7) and the ignition coil harness connector
EN19 (EN20) terminal No.2 with a multimeter.

(e)

Measure resistance between the ignition coil harness
connector EN19 (EN20) terminal No.2 and a reliable ground
with a multimeter. Check whether there is short to ground
circuit.

(f)

Measure voltage between the ignition coil harness connector
EN19 (EN20) terminal No.2 and a reliable ground with a
multimeter. Check whether there is short to power supply
circuit.
Standard Value:

Measurements

Standard Value

EN01 (3) / (7) -EN19/EN20 (2)
Resistance

0 Ω

Resistance Between EN19/EN20 (2)
and A Reliable Ground

10 kΩ or higher

Voltage Between EN19/EN20 (2) and
A Reliable Ground

0 V

Are the measured values specified values?

No

Repair the circuit fault.

Yes

Step 6

Turn the ignition switch to the "ST" position to observe whether the instrument displays engine speed?

2-528

Ignition System JL4G18-D

Engine

Note: Each time the ignition switch can not stay at the "ST" location
more than 5s, otherwise it will damage the starter motor.

Note: The scan tool can also be to diagnose. Turn the ignition
switch to the "ST" position to observe the scan tool data: Engine /
data list / "engine speed."

Speed not shown?

No

Go to step 10

Yes

Step 7

Check the crankshaft position sensor.

For inspection steps, refer to 

2.2.7.29

 

DTC P0321 P0322

Confirm the resistance is the specified value.

No

Replace the crankshaft position sensor. Refer
to 

2.10.8.2

 

Crankshaft Position Sensor

Replacement

Yes

Step 8

Check the crankshaft position sensor signal circuit.

For inspection steps, refer to 

2.2.7.29

 

DTC P0321 P0322

Normal?

No

Repair the circuit fault.

Yes

Step 9

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 10

Replace ECM.

Engine

Ignition System JL4G18-D

2-529

2.10.7.6 Spark Plug Diagnostic

A

B

C

D

FE02-2050b

Step 1

Remove the spark plug. Refer to 

2.10.8.4

 

Spark Plug Replacement

.

Next

Step 2

Check whether the terminal terminal A is bent or broken, pull the terminal to test whether the terminal A is
loose.

Next

Step 3

Check whether the B-insulator has arcing or signs of leakage, which is due to discharge between terminal
A and terminal B two ends.

Check whether there are following conditions:

(a)

Check the high-voltage damping line for damage.

(b)

Check whether the cylinder head spark plug groove is wet.
Whether there is engine oil, engine coolant or water. Damped
spark plug will cause arc discharge.

Next

Step 4

Check whether there is crack on the insulator B, otherwise it will cause discharge.

2-530

Ignition System JL4G18-D

Engine