Suzuki Grand Vitara JB627. Manual — part 39

1A-105 Engine General Information and Diagnosis:

DTC P0171 / P0172: System Too Lean / Too Rich (Sensor-1, Bank-1)

S6JB0B1104034

System and Wiring Diagram

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

DTC Detecting Condition and Trouble Area

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

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81

I6JB01110098-01

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 P0171 System Too Lean (Sensor-1, Bank-1):
Total fuel trim (short term + long term fuel trim) is larger than 127% for
more than 20 sec, or short term fuel trim is larger than 130% for more
than 30 sec.
(2 driving cycle detection logic)
DTC P0172 System Too Rich (Sensor-1, Bank-1):
Total fuel trim (short term + long term fuel trim) is smaller than 71%
for more than 20 sec, or short term fuel trim is larger than 70% for
more than 30 sec.
(2 driving cycle detection logic)

• Vacuum leakage
• Exhaust gas leakage
• Fuel pressure out of specification
• Fuel injector malfunction
• A/F sensor malfunction
• MAF sensor malfunction
• Intake & exhaust valve clearance
• Intake & exhaust valve
• Valve timing
• ECM

Engine General Information and Diagnosis: 1A-106

DTC Confirmation Procedure

WARNING

!

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

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

• Road test should be carried out by 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”.
• Intake air temperature: –10

°C (14 °F) to 80 °C (176 °F).

• Engine coolant temperature: 30

°C (86 °F) or more.

• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more).
• The following DTC is not detected: ECT sensor, CKP sensor, IAT sensor, MAP sensor, A/F sensor, A/

F sensor heater, TP sensor, barometric pressure sensor, MAF sensor, EGR system and CMP sensor.

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) Drive vehicle at 40 mph (60 km/h) or higher. (engine speed: 2500 – 3000 r/min.)
5) Keep above vehicle speed for 4 min. or more. (Throttle valve opening is kept constant in this step.)
6) Check if DTC and pending DTC exist by using scan tool. If not, check if oxygen sensor monitoring test has been

completed by using scan tool. If not in both of above checks (i.e., no DTC and pending DTC and oxygen sensor
monitoring test not completed), check vehicle condition (environmental) and repeat Step 3) through 6).

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

Intake system and exhaust system for leakage check
1) Check intake system and exhaust system for leakage.

Are intake system and exhaust system in good condition?

Go to Step 3.

Repair or replace
defective parts.

3

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

Is check result satisfactory?

Go to Step 4.

Repair or replace
defective parts.

4

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

in Section 1G”.

Is check result satisfactory?

Go to Step 5.

Faulty injection(s) or its
circuit.

5

MAF sensor visual inspection
1) Check MAF sensor and air intake system.

• Objects which block measuring duct and resistor of

MAF sensor.

• Other air flow which does not pass MAF sensor.

Are they in good condition?

Go to Step 6.

Repair or replace
defective part.

1A-107 Engine General Information and Diagnosis:

6

MAF sensor for performance check
1) With ignition switch turned OFF, connect scan tool to

DLC.

2) Start engine and warm up to normal operating

temperature.

3) Check MAF value using scan tool (Refer to “Scan Tool

Data” for normal value.).

Is each value within specified range?

Go to Step 7.

Go to “DTC P0101:
Mass Air Flow Circuit
Range / Performance”.

7

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.

• 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 8.

Repair or replace
defective wiring
harness.

8

A/F sensor adjusting resistor check
1) Check for 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?

Go to Step 9.

Replace A/F sensor
(bank-1).

9

Valves and valves clearance check
1) Check bank-1 intake & exhaust valve and valve

clearance referring to “Valve Lash (Clearance)
Inspection in Section 1D” and “Valves and Valve Guides
Inspection in Section 1D”.

Is check result satisfactory?

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

Repair or replace
defective parts.

Step

Action

Yes

No

Engine General Information and Diagnosis: 1A-108

DTC P0174 / P0175: System Too Lean / Too Rich (Sensor-1, Bank-2)

S6JB0B1104035

System and Wiring Diagram

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

DTC Detecting Condition and Trouble Area

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

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27

28

29

30

31

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38

39

40

32

1

2

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81

a

b

I6JB01110099-01

a. Adjusting resistor (+) circuit of A/F sensor (bank-2)

3. Ignition Switch

7. A/F sensor heater

11. A/F sensor element

b. Adjusting resistor (–) circuit of A/F sensor (bank-2)

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 P0174 System Too Lean (Sensor-1, Bank-2):
Total fuel trim (short term + long term fuel trim) is larger than 127% for
more than 20 sec, or short term fuel trim is larger than 130% for more
than 30 sec.
(2 driving cycle detection logic)
DTC P0175 System Too Rich (Sensor-1, Bank-2):
Total fuel trim (short term + long term fuel trim) is s smaller than 71%
for more than 20 sec, or short term fuel trim is larger than 70% for
more than 30 sec.
(2 driving cycle detection logic)

• Vacuum leakage
• Exhaust gas leakage
• Fuel pressure out of specification
• Fuel injector malfunction
• A/F sensor malfunction
• MAF sensor malfunction
• Intake & exhaust valve clearance
• Intake & exhaust valve
• Valve timing
• ECM