Infiniti FX35, FX50 (S51). Manual - part 805

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

EC-761

< DTC/CIRCUIT DIAGNOSIS >

[VK50VE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

1.

Turn ignition switch OFF.

2.

Check ground connection M95. Refer to Ground Inspection in 

GI-39, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT

1.

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

2.

Turn ignition switch ON.

3.

Check the voltage between A/F sensor 1 harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors E10, F10
• IPDM E/R harness connector E7
• 15 A fuse (No. 46)
• Harness for open or short between A/F sensor 1 and fuse

>> Repair or replace harness or connectors.

4.

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 5.

NO

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

5.

CHECK A/F SENSOR 1 HEATER

Refer to 

EC-762, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> GO TO 6.

6.

REPLACE A/F SENSOR 1

Replace malfunctioning A/F sensor 1.

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.

DTC

A/F sensor 1

Ground

Voltage

Bank

Connector

Terminal

P0031, P0032

1

F67

4

Ground

Battery voltage

P0051, P0052

2

F68

4

DTC

A/F sensor 1

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0031, P0032

1

F67

3

F110

3

Existed

P0051, P0052

2

F68

3

4

EC-762

< DTC/CIRCUIT DIAGNOSIS >

[VK50VE]

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

• 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

7.

CHECK INTERMITTENT INCIDENT

Perform 

GI-36, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000005237241

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.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

REPLACE A/F SENSOR 1

Replace malfunctioning A/F sensor 1.

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

Terminal

Resistance

3 and 4

1.98 - 2.66 

Ω

 [at 25

°

C (77

°

F)]

3 and 1, 2

∞

 

Ω

(Continuity should not exist)

4 and 1, 2

P0037, P0038, P0057, P0058 HO2S2 HEATER

EC-763

< DTC/CIRCUIT DIAGNOSIS >

[VK50VE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

P0037, P0038, P0057, P0058 HO2S2 HEATER

Description

INFOID:0000000005237242

SYSTEM DESCRIPTION

The ECM performs ON/OFF control of the heated oxygen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature. 

OPERATION

DTC Logic

INFOID:0000000005237243

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next test. 
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 more than 11 V at idle.

>> GO TO 2.

Sensor

Input signal to ECM

ECM function

Actuator

Camshaft position sensor
Crankshaft position sensor

Engine speed

Heated oxygen sensor 2 
heater control

Heated oxygen sensor 2 heater

Engine coolant temperature sensor

Engine coolant temperature

Mass air flow sensor

Amount of intake air

Engine speed

Heated oxygen sensor 2 heater

Above 3,600 rpm

OFF

Below 3,600 rpm after the following conditions are met.
• Engine: After warming up
• Keeping the engine speed between 3,500 and 4,000 rpm for 1 

minute and at idle for 1 minute under no load

ON

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0037

Heated oxygen sensor 2 
heater (bank 1) control 
circuit 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

Heated oxygen sensor 2 
heater (bank 1) control 
circuit 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

Heated oxygen sensor 2 
heater (bank 2) control 
circuit 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

Heated oxygen sensor 2 
heater (bank 2) control 
circuit 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

EC-764

< DTC/CIRCUIT DIAGNOSIS >

[VK50VE]

P0037, P0038, P0057, P0058 HO2S2 HEATER

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-764, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000005237244

1.

CHECK GROUND CONNECTION

1.

Turn ignition switch OFF.

2.

Check ground connection M95. Refer to Ground Inspection in 

GI-39, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

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.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors E10, F10
• IPDM E/R harness connector E7
• 15 A fuse (No. 46)
• Harness for open or short between heated oxygen sensor 2 and fuse

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

4.

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?

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

56

Existed

P0057, P0058

2

F88

3

55