Suzuki Grand Vitara JB627. Manual — part 41

1A-113 Engine General Information and Diagnosis:

DTC P0300 / P0301 / P0302 / P0303 / P0304 / P0305 / P0306: Misfire Detected

S6JB0B1104037

System Description
ECM measure the angle of the crankshaft based on the pulse signal from the CKP sensor and CMP sensor for each
cylinder. If it detects a large change in the angle speed of the crankshaft, it concludes occurrence of a misfire. When
the number of misfire is counted by ECM beyond the DTC detecting condition, it determine the cylinder where the
misfire occurred and output it as DTC.

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

WARNING

!

• When performing a road test, select a place where there is no traffic or possibility of a traffic

accident and very careful during testing to avoid occurrence of an accident.

• Road test should be carried out with 2 persons, a driver and a tester, on a level road.

NOTE
Check to make sure that the following conditions are satisfied when using this “DTC Confirmation
Procedure”.
• Atmospheric pressure: higher than 75 kpa (560 mmHg) (Altitude: lower than 2790 m (9150 ft)).
• Engine coolant temperature: higher than –10

°C (14 °F).

• Make sure that the ignition timing is good referring to “Ignition Timing Inspection in Section 1H”.

1) With ignition switch OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC by using scan tool if any.
3) Drive vehicle more than 37 mph (60 km/h) for more than 1 minute.
4) Stop vehicle and check DTC and pending DTC by using scan tool.

5

TP sensor check
1) Check TP sensor for performance referring to “Electric

Throttle Body Assembly On-Vehicle Inspection in
Section 1C”.

Is it in good condition?

Substitute a known
good ECM and recheck.

Replace electric throttle
body assembly.

Step

Action

Yes

No

DTC detecting condition

Trouble area

P0300: Random
• Misfire, which causes catalyst to overheat during 200 engine revolutions, is

detected at 2 or more cylinders. (MIL flashes as long as this misfire occurs
continuously.)

• Misfire, which affects exhaust emission adversely during 1000 engine revolutions,

is detected at 2 or more cylinders.

(2 driving cycle detection logic)

• Ignition system
• Fuel injector and its circuit
• Fuel pressure
• EGR system (if equipped)
• Fuel level sensor
• Abnormal air drawn in
• Engine compression
• Valve lash (clearance)
• Valve timing
• Fuel shortage
• Exhaust system
• Fuel of poor quality

P0301: No.1 cylinder, P0302: No.2 cylinder, P0303: No.3 cylinder, P0304: No.4
cylinder, P0305: No.5 cylinder, P0306: No.6 cylinder
• Misfire, which causes catalyst to overheat during 200 engine revolutions, is

detected at 1 cylinder. (MIL flashes as long as this misfire occurs continuously.)

• Misfire, which affects exhaust emission adversely during 1000 engine revolutions,

is detected at 1 cylinder.

(2 driving cycle detection logic)

Engine General Information and Diagnosis: 1A-114

DTC Troubleshooting

Step

Action

Yes

No

1

Was “Engine and Emission Control System Check”
performed?

Go to Step 2.

Go to “Engine and
Emission Control
System Check”.

2

Does fuel level meter indicate “E” level (empty)?

Add fuel and recheck.

Go to Step 3.

3

Air intake system and exhaust system inspection
1) Check air intake system and exhaust system for

leakage.

Are intake system and exhaust system in good condition?

Go to Step 4.

Repair or replace.

4

Ignition system inspection
1) Check spark plug and ignition spark of cylinder where

misfire occurs, referring to “Spark Plug Inspection in
Section 1H” and “Ignition Spark Check in Section 1H”.

Is it in good condition?

Go to Step 5.

Faulty ignition coil, wire
harness or spark plug. If
OK, substitute a known
good ECM and recheck.

5

Fuel injector and its circuit check
1) Check fuel injector circuit referring to “Fuel Injector

Circuit Check”.

Is it in good condition?

Go to Step 6.

Repair or replace.

6

Fuel pressure inspection
1) Check fuel pressure referring to “Fuel Pressure Check”.

Is check result satisfactory?

Go to Step 7.

Repair or replace.

7

Fuel injector inspection
1) Check fuel injector(s) referring to “Fuel Injector

Inspection in Section 1G”.

Is check result satisfactory?

Go to Step 8.

Replace.

8

EGR system inspection (if equipped)
1) Check EGR system referring to “EGR System Inspection

(If Equipped) in Section 1B”.

Is check result satisfactory?

Go to Step 9.

Repair or replace.

9

Fuel level sensor inspection
1) Check fuel level sensor referring to “Fuel Level Sensor

Inspection in Section 9C”.

Is check result satisfactory?

Go to Step 10.

Repair or replace.

10 Engine mechanical systems check

1) Check engine mechanical systems.

• Engine compression: Refer to “Compression Check in

Section 1D”.

• Valve lash: Refer to “Valve Lash (Clearance)

Inspection in Section 1D”.

• Valve timing: Refer to “LH (No.1) Bank 2nd Timing

Chain and Chain Tensioner Removal and Installation
in Section 1D” and “1st Timing Chain and Chain
Tensioner Removal and Installation in Section 1D”.

Are they in good condition?

Substitute a known
good ECM and recheck.

Repair or replace.

1A-115 Engine General Information and Diagnosis:

DTC P0327 / P0328: Knock Sensor Circuit Low / High

S6JB0B1104038

Wiring Diagram

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

1) Connect scan tool to DLC with ignition switch turned OFF.
2) Turn ON ignition switch and clear DTC pending DTC and freeze frame data by using scan tool.
3) Start engine and run it for 1 minute.
4) Check DTC by using scan tool.

1

2

5V

1

3 2

4

5

6

7

8

9

1110

12

13

14

15

16

17

18

19

20

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

33

34

35

36

37

38

39

40

32

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

E23

C37

C37-25

WHT

I5JB0C110011-01

1. Knock sensor

2. ECM

DTC detecting condition

Trouble area

DTC P0327: Knock Sensor Circuit Low
Output voltage of knock sensor is less than 1 V for more than 255
ignition times continuously.
(1 driving cycle detection logic)

• Knock sensor and its circuit
• ECM

DTC P0328: Knock Sensor Circuit High
Output voltage of knock sensor is more than 4 V for more than 255
ignition times continuously.
(1 driving cycle detection logic)

Engine General Information and Diagnosis: 1A-116

DTC Troubleshooting

NOTE
Before this trouble shooting is performed, read the precautions for DTC troubleshooting referring to
“Precautions for DTC Troubleshooting”.

Step

Action

Yes

No

1

Was “Engine and Emission Control System Check”
performed?

Go to Step 2.

Go to “Engine and
Emission Control
System Check”.

2

Knock sensor circuit voltage check
1) Turn ignition switch OFF position.
2) Disconnect connector from knock sensor.
3) Check for proper terminal connection to knock sensor

and ECM connectors

4) If connections are OK, turn ignition switch to ON

position.

5) Check that circuit voltage is 5 V between knock sensor

signal circuit of knock sensor connector and vehicle
body ground.

Is it in good condition?

Replace knock sensor. Go to Step 3.

3

Wire harness check
1) Disconnect connector from ECM with ignition switch

turned OFF.

2) Check that knock sensor signal circuit is as follows.

• Wiring harness resistance of knock sensor signal

circuit is less than 3

Ω.

• Insulation resistance of knock sensor signal circuit is

infinity between knock sensor connector and vehicle
body ground.

• Circuit voltage of knock sensor signal circuit is 0 – 1 V

with ignition switch turned ON.

Are they in good condition?

Substitute a known
good ECM and recheck.

Repair or replace
defective wire harness.