Suzuki Grand Vitara JB416 / JB420 / JB419. Manual — part 32

1A-75 Engine General Information and Diagnosis: For Petrol Engine Model

DTC P0037 / P0038: HO2S Heater Control Circuit Low / High (Sensor-2)

S6JB0A1114017

Wiring Diagram

10 A/F sensor heater control circuit check

1) Disconnect connector from ECM with ignition switch

turned OFF.

2) Check for proper connection of A/F sensor heater circuit

terminal to ECM connector.

3) If connection are OK, measure each wire resistance of

sensor heater control circuit at ECM connector between
ECM to A/F sensor and ECM to vehicle body ground.

Is each measured wire resistance lower than 1

Ω

?

Go to Step 11.

Repair or replace
defective wire circuit.

11 A/F sensor heater circuit check

1) Measure insulation resistance between control terminal

of A/F sensor heater and ground terminal of A/F sensor
heater at ECM connector.

Is measured resistance infinity?

Substitute a known
good ECM and recheck.

Repair or replace short
wire.

Step

Action

Yes

No

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

4

3

9

RED

GRN

PNK

BLK

C37-47

C37-11

C37-57

6

2

7

10

BLK

BLU

WHT

BLK/RED

GRY/GRN

1

8

5

5V

BLK/WHT

BLK

PNK

*GRN

I5JB0A110032-01

1. HO2S heater relay

4. “O2 HTR” fuse

7. Heater

10. To other sensors

2. Shield wire

5. “IG COIL” fuse

8. To A/F sensor heater

*: For M16 engine

3. Ignition switch

6. HO2S-2

9. ECM

Engine General Information and Diagnosis: For Petrol Engine Model 1A-76

DTC Detecting Condition and Trouble Area

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 warm up to normal operating temperature.
4) Run engine at idle speed for 1 min.
5) 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”.

DTC detecting condition

Trouble area

P0037:
HO2S-2 circuit voltage is lower than specification for 5 sec
continuously even though control duty ratio of HO2S-2 heater is less
than 75% with engine running. (Heater control duty pulse is not
detected in its monitor signal)
(2 driving cycle detection logic)
P0038:
HO2S-2 circuit voltage is higher than specification for 5 sec
continuously even though control duty ratio of HO2S-2 heater is more
than 25% with engine running. (Heater control duty pulse is not
detected in its monitor signal)
(2 driving cycle detection logic)

• HO2S-2 heater
• HO2S-2 heater circuit
• ECM

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

HO2S-2 heater circuit check
1) Disconnect connector from HO2S-2 with ignition switch

turned OFF.

2) Check for proper connection to HO2S-2 connector.
3) If connection are OK, measure voltage between heater

power terminal of HO2S-2 connector and vehicle body
ground with ignition switch turned ON.

Is measured voltage 10 – 14 V?

Go to Step 9.

Go to Step 3.

1A-77 Engine General Information and Diagnosis: For Petrol Engine Model

3

HO2S heater fuse check
1) Check for “O2 HTR” fuse (1) blown.

For J20 engine

For M16 engine

Is “O2 HTR” fuse in good condition?

Go to Step 5.

Go to Step 4.

4

A/F sensor and HO2S heater resistance check
1) Disconnect connector from A/F sensor with ignition

switch turned OFF.

2) Check heater resistance of A/F sensor and HO2S

referring to “Air Fuel Ratio (A/F) Sensor On-Vehicle
Inspection: For Petrol Engine Model in Section 1C” and
“Heated Oxygen Sensor (HO2S-2) Heater On-Vehicle
Inspection: For Petrol Engine Model in Section 1C”.

Are A/F sensor heater and HO2S heater in good condition?

Go to Step 6.

Replace defective
sensor.

Step

Action

Yes

No

1

I5JB0A110028-02

1

I5JB0A110029-02

Engine General Information and Diagnosis: For Petrol Engine Model 1A-78

5

HO2S heater relay power circuit check
1) Remove integration relay No.2 (for J20 engine) (1) or

HO2S heater relay (for M16 engine) (2) with ignition
switch turned OFF.

2) Check for proper connection to relay connector.
3) If connection are OK, measure voltage between each

relay power terminal of relay connector and vehicle body
ground with ignition switch tuned ON.

For J20 engine

For M16 engine

Is each measured voltage 10 – 14 V?

Go to Step 6.

Power circuit is open.

6

Check HO2S heater relay
1) Check integration relay No.2 (for J20 engine) or HO2S

heater relay (for M16 engine) referring to “Control Relay
Inspection: For Petrol Engine Model in Section 1C”.

Is it in good condition?

Go to Step 7.

Replace relay.

7

HO2S-2 heater circuit check
1) Measure insulation resistance between heater terminals

of HO2S-2 connector.

Is measured resistance infinity?

Go to Step 8.

Repair or replace short
wire.

8

HO2S heater relay circuit check
1) Measure wire resistance between coil ground terminal of

relay connector and vehicle body ground.

Is measured resistance lower than 1

Ω

?

Output wire of relay
connector is open or
short to ground.

Repair or replace
defective circuit.

9

HO2S-2 heater check
1) Check heater resistance of HO2S-2 referring to “Heated

Oxygen Sensor (HO2S-2) Heater On-Vehicle Inspection:
For Petrol Engine Model in Section 1C”.

Is HO2S-2 heater in good condition?

Go to Step 10.

Replace HO2S-2.

Step

Action

Yes

No

1

I5JB0A110030-02

2

I5JB0A110031-03