Suzuki Grand Vitara JB627. Manual — part 57

1A-177 Engine General Information and Diagnosis:

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

A/F sensor signal check
1) Connect scan tool with ignition switch turned OFF.
2) Warm up engine to normal operating temperature and

keep it at 2000 r/min. for 60 sec.

3) Repeat racing engine (Repeat depressing accelerator

pedal 5 to 6 times continuously to enrich A/F mixture and
take foot off from pedal to enlean it).

4) Check for A/F sensor (bank-2) output current displayed

on scan tool.

Does A/F sensor output current between –0.2 mA and 0.2
mA?

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

Go to Step 3.

3

A/F sensor circuit check
1) Disconnect connector from A/F sensor (bank-2) and

ECM with ignition switch turned OFF.

2) Check for proper terminal connection to A/F sensor

(bank-2) connector and ECM connector.

3) If connections are OK, check that A/F sensor (bank-2)

circuit is as follows.
• Wiring harness resistance of each “Signal (+) circuit of

A/F sensor (bank-2)”, “Signal (–) circuit of A/F sensor
(bank-2)” is less than 1

Ω.

• Insulation resistance between “Signal (–) circuit of A/F

sensor (bank-2)” and vehicle body ground is infinity.

• Insulation resistance between “Signal (+) circuit of A/F

sensor (bank-2)” and “Signal (–) circuit of A/F sensor
(bank-2)” is infinity.

• Insulation resistance of wire harness is infinity

between “Signal (+) circuit of A/F sensor (bank-2)”
terminal and each other terminal at A/F sensor (bank-
2) connector.

• Insulation resistance of wire harness is infinity

between “Signal (–) circuit of A/F sensor (bank-2)”
terminal and each other terminal at A/F sensor (bank-
2) connector.

• Circuit voltage between “Signal (–) circuit of A/F

sensor (bank-2)” and vehicle body ground is 0 V with
ignition switch tuned ON.

Are they in good condition?

Go to Step 4.

Repair or replace
defective wiring
harness.

4

A/F sensor heater check
1) Check A/F sensor (bank-2) referring to “Air Fuel Ratio

(A/F) Sensor On-Vehicle Inspection in Section 1C”.

Is A/F sensor in good condition?

Substitute a known
good ECM and recheck.
If ECM OK, replace A/F
sensor (bank-2).

Replace A/F sensor
(bank-2).

Engine General Information and Diagnosis: 1A-178

DTC P2627 / P2628: O2 Sensor Pumping Current Trim Circuit Low / High (Sensor-1, Bank-1)

S6JB0B1104076

System and Wiring Diagram

A/F Sensor Description
Refer to “A/F Sensor Description”

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

1) With ignition switch turned OFF, connect scan tool to DLC.
2) Turn ON ignition switch and clear DTC.
3) Start engine and warm up to normal operating temperature.
4) Run engine at idle speed for 1 min. or more.
5) Check DTC and pending DTC.

4

3

9

PNK

6

2

1

a

b

8

5

BLK/WHT

BLK

PNK

GRN

C37-16

C37-77

C37-19

C37-18

BLK

BLK

BLU

WHT

C37-17

C37-79

BLK

WHT

RED/YEL

RED/BLU

PNK/BLK

BLK/YEL

10

7

11

5 V

5 V

1

3 2

4

5

6

7

8

9

1110

12

13

14

15

16

17

18

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20

17

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32

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21

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68

69

70

71

72

73

74

75

76

77

78

79

80

81

I6JB01110106-01

a. Adjusting resistor (+) circuit of A/F sensor (bank-1)

3. Ignition Switch

7. A/F sensor heater

11. A/F sensor element

b. Adjusting resistor (–) circuit of A/F sensor (bank-1)

4. O2 HTR fuse

8. To A/F sensor (bank-2), HO2S (bank-1 and-2)

1. HO2S heater relay

5. IG COIL fuse

9. ECM

2. Shield wire

6. A/F sensor

10. Adjusting resistor (if equipped)

DTC detecting condition

Trouble area

DTC P2627 O2 Sensor Pumping Current Trim Circuit Low (Sensor-1, Bank-1):
Output voltage of A/F sensor adjusting resister is less than 0.1 V for more than 4 sec.
continuously with engine running.
(1 driving cycle detection logic)
DTC P2628 O2 Sensor Pumping Current Trim Circuit High (Sensor-1, Bank-1):
Output voltage of A/F sensor adjusting resister is more than 5 V for more than 4 sec.
continuously with engine running.
(1 driving cycle detection logic)

• A/F sensor malfunction
• A/F sensor circuit malfunction
• ECM

1A-179 Engine General Information and Diagnosis:

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

A/F sensor adjusting resistor circuit check
1) Disconnect connectors from A/F sensor (bank-1) and

ECM with ignition switch turned OFF.

2) Check for proper terminal connection to A/F sensor

(bank-1) connector and ECM connector.

3) If connections are OK, check that A/F sensor (bank-1)

adjusting resistor circuit is as follows.
• Wiring harness resistance of each “Adjusting resistor

(+) circuit of A/F sensor (bank-1)” and “Adjusting
resistor (–) circuit of A/F sensor (bank-1)” is less than
1

Ω.

• Insulation resistance between “Adjusting resistor (+)

circuit of A/F sensor (bank-1)” and vehicle body
ground is infinity.

• Insulation resistance between “Adjusting resistor (+)

circuit of A/F sensor (bank-1)” and “Adjusting resistor
(–) circuit of A/F sensor (bank-1)” is infinity.

• Insulation resistance of wire harness is infinity

between “Signal (+) circuit of A/F sensor (bank-1)”
terminal and each other terminal at A/F sensor (bank-
1) connector.

• Insulation resistance of wire harness is infinity

between “Signal (–) circuit of A/F sensor (bank-1)”
terminal and each other terminal at A/F sensor (bank-
1) connector.

• Circuit voltage between “Adjusting resistor (+) circuit

of A/F sensor (bank-1)” and vehicle body ground is 0
V with ignition switch tuned ON.

Are they in good condition?

Go to Step 3.

Repair or replace
defective wiring
harness.

3

A/F sensor adjusting resistor check
1) Check heater resistance of A/F sensor (bank-1)

adjusting resistor referring to “Air Fuel Ratio (A/F)
Sensor On-Vehicle Inspection in Section 1C”.

Is check result satisfactory?

Substitute a known
good ECM and recheck.
If ECM OK, replace A/F
sensor (bank-1).

Replace A/F sensor
(bank-1).

Engine General Information and Diagnosis: 1A-180

DTC P2630 / P2631: O2 Sensor Pumping Current Trim Circuit Low / High (Sensor-1, Bank-2)

S6JB0B1104077

System and Wiring Diagram

A/F Sensor Description
Refer to “A/F Sensor Description”

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

1) With ignition switch turned OFF, connect scan tool to DLC.
2) Turn ON ignition switch and clear DTC.
3) Start engine and warm up to normal operating temperature.
4) Run engine at idle speed for 1 min. or more.
5) Check DTC and pending DTC.

4

3

9

PNK

6

2

1

8

5

BLK/WHT

BLK

PNK

GRN

C37-35

C37-78

C37-38

C37-37

BLK

BLK

BLU

WHT

C37-36

C37-79

BRN

YEL

BLU/YEL

BLU/RED

PNK/BLU

BLK/YEL

10

7

11

5 V

5 V

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

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16

21

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73

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75

76

77

78

79

80

81

a

b

I6JB01110107-01

a. Adjusting resistor (+) circuit of A/F sensor (bank-1)

3. Ignition Switch

7. A/F sensor heater

11. A/F sensor element

b. Adjusting resistor (–) circuit of A/F sensor (bank-1)

4. O2 HTR fuse

8. To A/F sensor (bank-1), HO2S

(bank-1 and -2)

1. HO2S heater relay

5. IG COIL fuse

9. ECM

2. Shield wire

6. A/F sensor

10. Adjusting resistor (if equipped)

DTC detecting condition

Trouble area

DTC P2630 O2 Sensor Pumping Current Trim Circuit Low
(Sensor-1, Bank-2):
Output voltage of A/F sensor adjusting resister is less than 0.1 V
for more than 4 sec. continuously with engine running.
(1 driving cycle detection logic)
DTC P2631 O2 Sensor Pumping Current Trim Circuit High
(Sensor-1, Bank-2):
Output voltage of A/F sensor adjusting resister is more than 5 V
for more than 4 sec. continuously with engine running.
(1 driving cycle detection logic)

• A/F sensor malfunction
• A/F sensor circuit malfunction
• ECM