Infiniti QX56 (Z62). Manual - part 551

EC-182

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER

2.

DETECT MALFUNCTIONING PART

Check the following.
• 20 A fuse (No. 43)
• Harness for open or short between A/F sensor 1 and fuse
• Loose or poor connection for each connector and harness

>> Repair or replace harness or connectors.

3.

CHECK A/F SENSOR 1 HEATER OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

4.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 4.

NO

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

4.

CHECK A/F SENSOR 1 HEATER

Refer to 

EC-182, "Component Inspection (A/F Sensor 1 Heater)"

.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> GO TO 5.

5.

REPLACE A/F SENSOR 1

Replace malfunctioning A/F sensor 1. Refer to 

EM-40, "Exploded View"

.

CAUTION:

• Discard any A/F 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 A/F sensor, clean exhaust system threads using Oxygen Sensor Thread

Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant
(commercial service tool).

>> INSPECTION END

6.

CHECK INTERMITTENT INCIDENT

Perform 

GI-40, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection (A/F Sensor 1 Heater)

INFOID:0000000006217777

1.

CHECK AIR FUEL RATIO (A/F) SENSOR 1

1.

Turn ignition switch OFF.

2.

Disconnect air fuel ratio (A/F) sensor 1 harness connector.

3.

Check resistance between A/F sensor 1 terminals as per the following.

DTC

A/F sensor 1

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0031, P0032

1

F67

2

F110

48

Existed

P0051, P0052

2

F68

2

53

Terminal

Resistance

2 and 5

2.0 - 3.2 

Ω

 [at 25

°

C (77

°

F)]

P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER

EC-183

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

REPLACE A/F SENSOR 1

Replace malfunctioning A/F sensor 1. Refer to 

EM-40, "Exploded View"

.

CAUTION:

• Discard any A/F 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 A/F sensor, clean exhaust system threads using Oxygen Sensor Thread

Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant
(commercial service tool).

>> INSPECTION END

2 and 3, 4, 6

∞

 

Ω

(Continuity should not exist)

5 and 3, 4, 6

Terminal

Resistance

EC-184

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0037, P0038, P0057, P0058 HO2S2 HEATER

P0037, P0038, P0057, P0058 HO2S2 HEATER

DTC Logic

INFOID:0000000006217778

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON.

3.

Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

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

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Turn ignition switch ON.

4.

Turn ignition switch OFF and wait at least 10 seconds.

5.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

6.

Let engine idle for 1 minute.

7.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-184, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006217779

1.

CHECK HEATED OXYGEN SENSOR 2 (HO2S2) POWER SUPPLY CIRCUIT

1.

Disconnect heated oxygen sensor 2 (HO2S2) harness connector.

2.

Turn ignition switch ON.

3.

Check the voltage between HO2S2 harness connector and ground.

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P0037

HO2S2 HTR (B1)
[Heated oxygen sensor 2 
heater (bank 1) control cir-
cuit low]

The current amperage in the heated oxygen sensor 
2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM 
through the heated oxygen sensor 2 heater.)

• Harness or connectors

(The heated oxygen sensor 2 heater 
circuit is open or shorted.)

• Heated oxygen sensor 2 heater

P0038

HO2S2 HTR (B1)
[Heated oxygen sensor 2 
heater (bank 1) control cir-
cuit high]

The current amperage in the heated oxygen sensor 
2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM 
through the heated oxygen sensor 2 heater.)

• Harness or connectors

(The heated oxygen sensor 2 heater 
circuit is shorted.)

• Heated oxygen sensor 2 heater

P0057

HO2S2 HTR (B2)
[Heated oxygen sensor 2 
heater (bank 2) control cir-
cuit low]

The current amperage in the heated oxygen sensor 
2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM 
through the heated oxygen sensor 2 heater.)

• Harness or connectors

(The heated oxygen sensor 2 heater 
circuit is open or shorted.)

• Heated oxygen sensor 2 heater

P0058

HO2S2 HTR (B2)
[Heated oxygen sensor 2 
heater (bank 2) control cir-
cuit high]

The current amperage in the heated oxygen sensor 
2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM 
through the heated oxygen sensor 2 heater.)

• Harness or connectors

(The heated oxygen sensor 2 heater 
circuit is shorted.)

• Heated oxygen sensor 2 heater

P0037, P0038, P0057, P0058 HO2S2 HEATER

EC-185

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 2.

2.

DETECT MALFUNCTIONING PART

Check the following.
• 20 A fuse (No. 43)
• Harness for open or short between heated oxygen sensor 2 and fuse
• Loose or poor connection for each connector and harness

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

3.

CHECK HO2S2 OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between HO2S2 harness connector and ECM harness connector.

4.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 4.

NO

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

4.

CHECK HO2S2 HEATER

Refer to 

EC-186, "Component Inspection (HO2 Sensor 2 Heater)"

.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> GO TO 5.

5.

REPLACE HEATED OXYGEN SENSOR 2

Replace malfunctioning heated oxygen sensor 2. Refer to 

EX-5, "Removal and Installation"

.

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 [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant
(commercial service tool).

>> INSPECTION END

6.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

>> INSPECTION END

DTC

HO2S2

Ground

Voltage

Bank

Connector

Terminal

P0037, P0038

1

F87

2

Ground

Battery voltage

P0057, P0058

2

F88

2

DTC

HO2S2

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0037, P0038

1

F87

3

F111

47

Existed

P0057, P0058

2

F88

3

52