Suzuki Grand Vitara JB416 / JB420 / JB419. Service manual - part 36

1A-91 Engine General Information and Diagnosis: For Petrol Engine Model

DTC P0111: Intake Air Temperature Circuit Range / Performance

S6JB0A1114024

Wiring Diagram

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure 

NOTE
Check to make sure that following conditions are satisfied when using this “DTC Confirmation 
Procedure”.
• Intake air temperature at engine start: –10 

°C (14 °F) to 80 °C (176 °F)

• Intake air temperature: –10 

°C (14 °F) to 70 °C (158 °F)

• Engine coolant temperature at engine start: less than 30 

°C (86 °F)

• Engine coolant temperature: 70 

°C (158 °F) to 150 °C (302 °F)

• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)

 

1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch, clear DTC using scan tool.
3) Start engine and warm up to normal operating temperature. (ECT approx. 90 – 95 

°C, 194 – 203 °F)

4) Run engine at idle speed for 10 min. or more.
5) Check DTC and pending DTC.

E23

C37

3

4

18

19

5

6

7

10

11

17

20

47

46

49

50

51

21

22

52

16

25

9

24

14
29

55

57

54 53

59

60

58

2

26

27

28

15
30

56

48

32

31

34

35

36

37

40

42

39 38

44

45

43

41

33

1

12

13

23

8

3

4

18

19

5

6

7

10

11

17

20

47

46

49

50

51

21

22

52

16

25

9

24

14
29

55

57

54 53

59

60

58

2

26

27

28

15
30

56

48

32

31

34

35

36

37

40

42

39 38

44

45

43

41

33

1

12

13

23

8

5V

LT GRN

GRY/GRN

GRY/GRN

1

BLU/BLK

C37-25  

C37-57  

3

BLU

RED

C37-26  

C37-27  

4

2

I5JB0A110036-01

1. MAF and IAT sensor

3. To other sensors

2. ECM

4. From main relay

DTC detecting condition

Trouble area

Difference of maximum IAT minus minimum IAT is less than 0.3 

°C 

(32.5 

°F) while ECT is over 70 °C (158 °F) after 10 min from cold 

engine start (ECT is lower than 30

°C (86 °F) at engine start).

(2 driving cycle detection logic)

• High resistance circuit
• MAF and IAT sensor
• ECM

Engine General Information and Diagnosis: For Petrol Engine Model 1A-92

DTC Troubleshooting

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

 

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: For 
Petrol Engine Model”.

2

IAT sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned 

OFF.

2) Turn ignition switch to ON position.
3) Check intake air temp. displayed on scan tool.

Is –40 

°

C (–40 

°

F) or 119 

°

C (246 

°

F) indicated?

Go to Step 3.

Intermittent trouble.
Check for intermittent 
referring to “Intermittent 
and Poor Connection 
Inspection in Section 
00”.

3

Wire harness check
1) Disconnect MAF and IAT sensor connector (1) with 

ignition switch turned OFF.

2) Check for proper connection to MAF and IAT sensor 

connector (1) at “LT GRN” and “GRY/GRN” wire 
terminals.

3) If OK, then with ignition switch turned ON, measure 

voltage between “LT GRN” wire terminal of MAF and IAT 
sensor connector and vehicle body ground.

Is measured voltage applied to “LT GRN” wire terminal about 
4 – 6 V?

Go to Step 8.

Go to Step 4.

4

ECM voltage check
1) Turn OFF ignition switch.
2) Remove ECM from its bracket with ECM connectors 

connected.

3) Check for proper connection of ECM connector at “C37-

25” terminal.

4) If OK, then turn ON ignition switch, measure voltage 

between “C37-25” terminal of ECM connector and 
vehicle body ground.

Is voltage about 4 – 6 V at terminal?

“LT GRN” wire is open 
circuit.
If wire and connection 
are OK, go to Step 5.

Go to Step 5.

I5JB0A110037-02

1A-93 Engine General Information and Diagnosis: For Petrol Engine Model

DTC P0112: Intake Air Temperature Sensor Circuit Low

S6JB0A1114025

Wiring Diagram
Refer to “DTC P0111: Intake Air Temperature Circuit Range / Performance: For Petrol Engine Model”.

DTC Detecting Condition and Trouble Area

5

Wire circuit check
1) Disconnect connectors from ECM with ignition switch 

turned OFF.

2) Measure resistance between “LT GRN” wire terminal of 

MAF and IAT sensor connector and vehicle body 
ground.

Is resistance infinity?

Go to Step 6.

“LT GRN” wire is 
shorted to ground or 
other circuit.
If wire is OK, substitute 
a known-good ECM and 
recheck.

6

Wire circuit check
1) Turn ignition switch to ON position.
2) Measure voltage between “LT GRN” wire terminal of 

MAF and IAT sensor connector and vehicle body 
ground.

Is voltage about 0 V?

Go to Step 7.

“LT GRN” wire shorted 
to other circuit.
If wire is OK, substitute 
a known-good ECM and 
recheck.

7

Wire circuit check
1) Measure resistance between “C37-25” terminal of ECM 

connector and “LT GRN” wire terminal of MAF and IAT 
sensor connector with ignition switch turned OFF.

Is resistance below 3 

Ω

?

Go to Step 8.

“LT GRN” wire is high 
resistance circuit.

8

Ground circuit check
1) Connect connectors to ECM.
2) Check for proper connection of MAF and IAT sensor 

connector at “GRY/GRN” wire terminal.

3) Measure resistance between “GRY/GRN” wire terminal 

of MAF and IAT sensor connector and vehicle body 
ground with ignition switch turned OFF.

Is resistance below 5 

Ω

?

Go to Step 10.

Go to Step 9.

9

Ground circuit check
1) Remove ECM from its bracket with ECM connectors 

connected.

2) Measure resistance between “C37-57” terminal of ECM 

connector and vehicle body ground.

Is resistance below 3 

Ω

?

“GRY/GRN” wire is 
open or high resistance 
circuit.
Poor “C37-57” 
connection.

Faulty ECM ground 
circuit.
If circuit is OK, 
substitute a known-
good ECM and recheck.

10 IAT sensor check

1) Check IAT sensor according to “Mass Air Flow (MAF) 

and Intake Air Temperature (IAT) Sensor Inspection: For 
Petrol Engine Model in Section 1C”.

Is it in good condition?

Substitute a known-
good ECM and recheck.

Replace MAF and IAT 
sensor.

Step

Action

Yes

No

DTC detecting condition

Trouble area

Voltage of IAT sensor output is less than 0.2 V for 0.5 sec 
continuously (High intake air temperature (low voltage / low 
resistance))
(1 driving cycle detection logic)

• IAT sensor circuit
• IAT sensor
• ECM

Engine General Information and Diagnosis: For Petrol Engine Model 1A-94

DTC Confirmation Procedure

1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and run it for 10 sec.
4) Check DTC and pending DTC.

DTC Troubleshooting

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

 

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: For 
Petrol Engine Model”.

2

IAT sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned 

OFF.

2) Turn ON ignition switch.
3) Check intake air temp. displayed on scan tool.

Is 119 

°

C (246 

°

F) indicated?

Go to Step 3.

Intermittent trouble.
Check for intermittent 
referring to “Intermittent 
and Poor Connection 
Inspection in Section 
00”.

3

ECM voltage check
1) Disconnect connector from MAF and IAT sensor with 

ignition switch turned OFF.

2) Check for proper connection to MAF and IAT sensor at 

“LT GRN” and “GRY/GRN” wire terminals.

3) If OK, then turn ON ignition switch, measure voltage 

between “LT GRN” wire terminal of MAF and IAT sensor 
connector (1) and vehicle body ground.

Is voltage about 4 – 6 V?

Go to Step 6.

Go to Step 4.

4

IAT short circuit check
1) Disconnect connectors from ECM with ignition switch 

turned OFF.

2) Measure resistance between “LT GRN” wire terminal of 

MAF and IAT sensor connector and vehicle body 
ground.

Is resistance infinity?

Go to Step 5.

“LT GRN” wire is 
shorted to ground 
circuit.
If wire is OK, substitute 
a known-good ECM and 
recheck.

I5JB0A110037-02