Suzuki Grand Vitara JB627. Manual - part 68

1A-221 Engine General Information and Diagnosis: 

Reference waveform No.25
Throttle actuator output signals:

Reference waveform No.26
Throttle actuator output signals:

Reference waveform No.27
CAN communication line signals:

Reference waveform No.28
Start (1), CKP sensor (2), CMP sensor (3) and ignition 
coil No.1 (4) signals:

Measurement 
terminal

CH1: E23-4 to C37-81
CH2: E23-5 to C37-81

Oscilloscope 
setting

CH1: 5 V/DIV, CH2: 5 V/DIV,
TIME: 100 

µs/DIV

Measurement 
condition

Ignition switch is at ON position and 
accelerator pedal is not depressed 
after warmed up engine.

1. Throttle actuator drive signal (E23-4 terminal)
2. Throttle actuator drive signal (E23-5 terminal)
3. One duty cycle

Measurement 
terminal

CH1: E23-4 to C37-81
CH2: E23-5 to C37-81

Oscilloscope 
setting

CH1: 5 V/DIV, CH2: 5 V/DIV
TIME: 100 

µs/DIV

Measurement 
condition

Ignition switch is at ON position and 
accelerator pedal is at fully 
depressed after warmed up engine.

1. Throttle actuator drive signal (E23-4 terminal)
2. Throttle actuator drive signal (E23-5 terminal)
3. One duty cycle

I6JB01110088-01

I6JB01110089-02

Measurement 
terminal

CH1: E23-9 to C37-81
CH2: E23-17 to C37-81

Oscilloscope 
setting

CH1: 1 V/DIV, CH2: 1V/DIV
TIME: 40 

µs/DIV

Measurement 
condition

Ignition switch is at ON position. 
(Signal pattern is depending on 
communication data.)

1. CAN communication line signal (high)
2. CAN communication line signal (low)

Measurement 
terminal

CH1: C37-28 to C37-81
CH2: C37-47 to C37-81
CH3: C37-66 to C37-81
CH4: C37-15 to C37-81

Oscilloscope 
setting

CH1: 10 V/DIV, CH2: 5 V/DIV,
CH3: 5 V/DIV, CH4: 5 V/DIV
TIME: 100 ms/DIV

Measurement 
condition

Engine is at cranking.

I6JB01110090-02

I6JB01110093-02

Engine General Information and Diagnosis:  1A-222

Reference waveform No.29
Start (1), CKP sensor (2), CMP sensor (3) and fuel 
injector No.1 (4) signals:

Resistance Check

1) Remove ECM from its bracket referring to “Engine Control Module (ECM) Removal and Installation in Section 1C”.

CAUTION

!

 

Never touch terminals of ECM itself or connect voltmeter or ohmmeter (2).

 

2) Connect special tool (A) to ECM connectors (1) securely.

Special tool
(A):  09933–06520

NOTE
Do not connect the other connector of special tool to ECM.

 

3) Check resistance between each pair of terminals of special tool connectors as listed in the following table.

CAUTION

!

 

• Be sure to connect ohmmeter probe from wire harness side of coupler.
• Be sure to turn OFF ignition switch for this check.
• Resistance in the following table represents that measured when parts temperature is 20 

°C (68 °F).

 

Measurement 
terminal

CH1: C37-28 to C37-81
CH2: C37-47 to C37-81
CH3: C37-66 to C37-81
CH4: C37-15 to C37-81

Oscilloscope 
setting

CH1: 10 V/DIV, CH2: 5 V/DIV,
CH3: 5 V/DIV, CH4: 10 V/DIV
TIME: 100 ms/DIV

Measurement 
condition

Engine is at cranking.

I6JB01110094-02

1

(A)

I6JB01110116-02

Terminals

Circuit

Standard 

resistance

Condition

E23-16 to E23-8

Main relay

160 – 240 

Ω

Battery disconnected and ignition 
switch turned ON

E23-24 to E23-8

Fuel pump relay

160 – 240 

Ω

—

E23-6 to E23-8

Throttle actuator control relay

160 – 240 

Ω

—

C37-15 to E23-2/3

Fuel injector No.1

10 – 14 

Ω

—

C37-34 to E23-2/3

Fuel injector No.2

10 – 14 

Ω

—

C37-14 to E23-2/3

Fuel injector No.3

10 – 14 

Ω

—

1A-223 Engine General Information and Diagnosis: 

ECM Power and Ground Circuit Check

S6JB0B1104085

Wiring Diagram

Circuit Description
When the ignition switch is turned ON, the main relay turns ON (the contact point closes) and the main power is 
supplied to ECM. And then ECM supplies 5 V power to each sensor (MAP sensor, A/C refrigerant pressure sensor, TP 
sensor).
If 5 V power circuit to each sensors from ECM is shorted to ground, ECM stops engine and emission control operation.

C37-33 to E23-2/3

Fuel injector No.4

10 – 14 

Ω

—

C37-13 to E23-2/3

Fuel injector No.5

10 – 14 

Ω

—

C37-32 to E23-2/3

Fuel injector No.6

10 – 14 

Ω

—

C37-12 to E23-2/3

EGR valve (stepping motor No.1 coil) 
(if equipped)

20 – 24 

Ω

—

C37-31 to E23-2/3

EGR valve (stepping motor No.2 coil) 
(if equipped)

20 – 24 

Ω

—

C37-11 to E23-2/3

EGR valve (stepping motor No.3 coil) 
(if equipped)

20 – 24 

Ω

—

C37-30 to E23-2/3

EGR valve (stepping motor No.4 coil) 
(if equipped)

20 – 24 

Ω

—

C37-10 to E23-2/3

EVAP canister purge valve

25 – 30 

Ω

—

C37-29 to E23-2/3

IMT vacuum solenoid valve

33 – 45 

Ω

—

Terminals

Circuit

Standard 

resistance

Condition

BLU/BLK

BLU/BLK

BLU/BLK

BLK/RED

BLK/RED

BLK/RED

BLU

12V 5V

2

1

14

4

3

6

10

11

12

WHT

E23-1  

E23-8  

E23-16

C37-49
C37-68

C37-48

C37-67

E23-2 
E23-3 

E23-5 
E23-4 

WHT/GRN

GRY/RED

RED/WHT

GRY/BLK

GRY/GRN

BLU/YEL

BLU/RED

5

C37-59

C37-58

C37-39

C37-73

C37-80

BLK/YEL

BLK/ORN

BLK/ORN

BLK/YEL
BLK/YEL

BLK

WHT

GRN

RED

WHT

WHT

8

7

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

9

C37-45
C37-46

C37-65
C37-64

E23

C37

BLK/ORN

C37-81

BLK/YEL

BLK/WHT

13

15

I5JB0C110015-01

1. Fuse box No.2

5. “IG COIL” fuse

9. “DOME” fuse

13. Throttle actuator motor

2. Ignition switch

6. ECM

10. DLC

14. TP sensor (main)

3. Main relay

7. “IG ACC” fuse

11. MAP sensor (if equipped)

15. TP sensor (sub)

4. Junction block

8. “FI” fuse

12. A/C refrigerant pressure sensor (if equipped)

Engine General Information and Diagnosis:  1A-224

Troubleshooting

NOTE

• Before performed troubleshooting, be sure to read the “Precautions of ECM Circuit Inspection”.
• When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the 

special tool to ECM and/or the ECM connectors referring to “Inspection of ECM and Its Circuits”.

 

Step

Action

Yes

No

1

Circuit fuse check
1) Disconnect connectors from ECM with ignition switch 

turned OFF.

2) Check for proper connection to ECM connector at “E23-

1”, “E23-2”, “E23-3”, “E23-8”, “E23-16”, “C37-39”, “C37-
58”, “C37-59”, “C37-73”, “C37-80” and “C37-81” 
terminals.

3) If OK, check “RADIO” fuse and “IG COIL” fuse for 

blowing.

Are “DOME” fuse and “IG COIL” fuse in good condition?

Go to Step 2.

Replace fuse (s) and 
check for short in 
circuits connected to 
fuse(s).

2

Power supply circuit check
1) Measure voltage between “E23-1” terminal of ECM 

connector and body ground.

Is voltage 10 – 14 V?

Go to Step 3.

“WHT” wire is open 
circuit.

3

Ignition signal check
1) Turn ignition switch to ON position.
2) Measure voltage between “E23-8” terminal of ECM 

connector and body ground.

Is voltage 10 – 14 V?

Go to Step 4.

“BLK/WHT” or “BLK/
YEL” wire is open 
circuit.

4

Main relay circuit check
1) Turn ignition switch to OFF position.
2) Check “FI” fuse (1) in fuse box No.2 for blowing.

3) If OK, measure voltage between “E23-16” terminal of 

ECM connector and body ground.

Is voltage 10 – 14 V?

Go to Step 5.

Go to Step 9.

5

Main relay circuit check
1) Connect connectors to ECM with ignition switch turned 

OFF.

2) Turn ignition switch to ON position.
3) Measure voltage between “E23-16” terminal of ECM 

connector and body ground.

Is voltage 0 – 1 V?

Go to Step 7.

Go to Step 6.

1

I5JB0C110016-01