Infiniti QX56 (JA60). Manual - part 376

EC-156

< COMPONENT DIAGNOSIS >

[VK56DE]

P0137, P0157 HO2S2

If not, warm up engine and go to next step when “COOLAN TEMP/S” indication reaches to 70

°C (158°F).

7. Open engine hood.
8. Select “HO2S2 (B1) P1147” (for DTC P0137) or “HO2S2 (B2) P1167” (for DTC P0157) of “HO2S2” in

“DTC WORK SUPPORT” mode with CONSULT-III.

9. Start engine and following the instruction of CONSULT-III.

NOTE:

It will take at most 10 minutes until “COMPLETED” is displayed.

10. Make sure that “OK” is displayed after touching “SELF-DIAG RESULTS”.

If “NG” is displayed, refer to 

EC-156, "Diagnosis Procedure"

.

If “CAN NOT BE DIAGNOSED” is displayed, perform the following.

a. Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).
b. Return to step 1.

Overall Function Check

INFOID:0000000005149175

Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st

trip DTC might not be confirmed.

 WITH GST

1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
4. Let engine idle for 1 minute.
5. Set voltmeter probes between ECM terminal 55 [HO2S2 (B1) signal] or 74 [HO2S2 (B2) signal] and

ground.

6. Check the voltage when revving up to 4,000 rpm under no load

at least 10 times.

(Depress and release accelerator pedal as soon as possible.)

The voltage should be above 0.58 V at least once during

this procedure.

If the voltage can be confirmed in step 6, step 7 is not nec-

essary.

7. Keep vehicle at idling for 10 minutes, then check the voltage. Or

check the voltage when coasting from 80 km/h (50 MPH) in D

position.

The voltage should be above 0.58V at least once during this

procedure.

8. If NG, go to 

EC-156, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005149176

1.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten three ground screws on the body.

Refer to 

EC-85, "Ground Inspection"

.

OK or NG

OK

>> GO TO 2.

PBIB2054E

BBIA0354E

P0137, P0157 HO2S2

EC-157

< COMPONENT DIAGNOSIS >

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NG

>> Repair or replace ground connections.

2.

CLEAR THE SELF-LEARNING DATA

 With CONSULT-III

1. Start engine and warm it up to normal operating temperature.

2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CONSULT-III.

3. Clear the self-learning control coefficient by touching “CLEAR”.

4. Run engine for at least 10 minutes at idle speed.

Is the 1st trip DTC P0171 or P0174 detected?

Is it difficult to start engine?

 Without CONSULT-III

1. Start engine and warm it up to normal operating temperature.

2. Turn ignition switch OFF.

3. Disconnect mass air flow sensor harness connector, and restart

and run engine for at least 5 seconds at idle speed.

4. Stop engine and reconnect mass air flow sensor harness con-

nector.

5. Make sure DTC P0102 is displayed.

6. Erase the DTC memory. Refer to 

EC-55, "Malfunction Indicator

Lamp (MIL)"

.

7. Make sure DTC P0000 is displayed.

8. Run engine for at least 10 minutes at idle speed.

Is the 1st trip DTC P0171 or P0174 detected?

Is it difficult to start engine?

Yes or No

Yes

>> Perform trouble diagnosis for DTC P0171 or P0174. Refer to 

EC-172

.

No

>> GO TO 3.

3.

CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect heated oxygen sensor 2 (HO2S2) harness connector.

3. Disconnect ECM harness connector.

4. Check harness continuity between ECM terminal 78 and HO2S2 terminal 4.

Refer to Wiring Diagram.

5. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 4.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

4.

CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check harness continuity between ECM terminal and HO2S2 terminal as follows.

Refer to Wiring Diagram.

BBIA0368E

Continuity should exist.

BBIA0435E

EC-158

< COMPONENT DIAGNOSIS >

[VK56DE]

P0137, P0157 HO2S2

2. Check harness continuity between the following terminals and ground.

Refer to Wiring Diagram.

3. Also check harness for short to power.
OK or NG

OK

>> GO TO 5.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

5.

CHECK HEATED OXYGEN SENSOR 2

Refer to 

EC-158, "Component Inspection"

.

OK or NG

OK

>> GO TO 6.

NG

>> Replace malfunctioning heated oxygen sensor 2.

6.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-35, "How to Check Terminal"

 and 

GI-38, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000005149177

HEATED OXYGEN SENSOR 2

 With CONSULT-III

1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
2. Start engine and warm it up to the normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.

6. Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select “HO2S2 (B1)/(B2)” as the monitor item

with CONSULT-III.

DTC

Terminals

Bank

ECM

Sensor

P0137

55

1

1

P0157

74

1

2

Continuity should exist.

DTC

Terminals

Bank

ECM

Sensor

P0137

55

1

1

P0157

74

1

2

Continuity should not exist.

P0137, P0157 HO2S2

EC-159

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7. Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to 

±25%.

“HO2S2 (B1)/(B2)” should be above 0.58 V at least once when the “FUEL INJECTION” is +25%.

“HO2S2 (B1)/(B2)” should be below 0.18 V at least once when the “FUEL INJECTION” is 

−25%.

CAUTION:

• Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7

in) onto a hard surface such as a concrete floor; use a new one.

• Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread

Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.

 Without CONSULT-III

1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
4. Let engine idle for 1 minute.
5. Set voltmeter probes between ECM terminal 55 [HO2S2 (B1) signal] or 74 [HO2S2 (B2) signal] and

ground.

6. Check the voltage when revving up to 4,000 rpm under no load

at least 10 times.

(Depress and release accelerator pedal as soon as possible.)

The voltage should be above 0.58 V and below 0.18 V at

least once during this procedure.

If the voltage can be confirmed at step 6, step 7 is not nec-

essary.

7. Keep vehicle at idling for 10 minutes, then check voltage. Or

check the voltage when coasting from 80 km/h (50 MPH) in D

position.

The voltage should be above 0.58 V and below 0.18 V at

least once during this procedure.

8. If NG, replace heated oxygen sensor 2.

CAUTION:

• Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7

in) onto a hard surface such as a concrete floor; use a new one.

• Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread

Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.

JMBIA0605GB

PBIB2054E