Infiniti G37 Coupe. Manual - part 494

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

EC-157

< COMPONENT DIAGNOSIS >

[VQ37VHR]

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

>> INSPECTION END

7.

CHECK INTERMITTENT INCIDENT

Perform 

GI-38, "Intermittent Incident"

.

>> Repair or replace.

Component Inspection

INFOID:0000000001733986

1.

CHECK AIR FUEL RATIO (A/F) SENSOR 1

1.

Turn ignition switch OFF.

2.

Disconnect A/F sensor 1 harness connector.

3.

Check resistance between A/F sensor 1 terminals as follows.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

REPLACE AIR FUEL RATIO (A/F) SENSOR 1

Replace malfunctioning air fuel ratio (A/F) sensor 1.

CAUTION:

• Discard any air fuel ratio (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 air fuel ratio (A/F) sensor, clean exhaust system threads using Heated Oxygen

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

>> INSPECTION END

Terminal

Resistance

3 and 4

1.8 - 2.44 

Ω

 [at 25

°

C (77

°

F)]

3 and 1, 2

∞Ω

(Continuity should not exist)

4 and 1, 2

EC-158

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P0037, P0038, P0057, P0058 HO2S2 HEATER

P0037, P0038, P0057, P0058 HO2S2 HEATER

Description

INFOID:0000000001733987

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:0000000001733988

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing 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 between 11V and 16V at
idle.

>> GO TO 2.

Sensor

Input signal to ECM

ECM function

Actuator

Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)

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 rpm

Heated oxygen sensor 2 heater

Above 3,600

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 sen-
sor 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 sen-
sor 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 sen-
sor 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 sen-
sor 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-159

< COMPONENT DIAGNOSIS >

[VQ37VHR]

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2.

PERFORM DTC CONFIRMATION PROCEDURE

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.

Turn ignition switch ON.

5.

Turn ignition switch OFF and wait at least 10 seconds.

6.

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

7.

Let engine idle for 1 minute.

8.

Check 1st trip DTC.

 With GST

Follow the procedure “With CONSULT-III” above.

Is 1st tip DTC detected?

YES

>> Go to 

EC-159, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001733989

1.

CHECK GROUND CONNECTION

1.

Turn ignition switch OFF.

2.

Check ground connection M95. Refer to Ground Inspection in 

GI-41, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

CHECK HO2S2 POWER SUPPLY CIRCUIT

1.

Disconnect heated oxygen sensor 2 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 E3, F1
• IPDM E/R harness connector E7
• 15A fuse (No. 46)
• Harness for open or short between heated oxygen sensor 2 and fuse

>> Repair open circuit or 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.

DTC

HO2S2

Ground

Voltage

Bank

Connector

Terminal

P0037, P0038

1

F54

2

Ground

Battery voltage

P0057, P0058

2

F53

2

EC-160

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P0037, P0038, P0057, P0058 HO2S2 HEATER

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 or short to ground or short to power in harness or connectors.

5.

CHECK HEATED OXYGEN SENSOR 2 HEATER

Refer to 

EC-160, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> GO TO 6.

6.

REPLACE HEATED OXYGEN SENSOR 2

Replace malfunctioning 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.

>> INSPECTION END

7.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-38, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000001733990

1.

CHECK HEATED OXYGEN SENSOR 2 HEATER

1.

Turn ignition switch OFF.

2.

Disconnect heated oxygen sensor 2 harness connector.

3.

Check resistance between HO2S2 terminals as follows.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

REPLACE HEATED OXYGEN SENSOR 2

Replace malfunctioning 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.

DTC

HO2S2

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0037, P0038

1

F54

3

F101

17

Existed

P0057, P0058

2

F53

3

33

Terminal

Resistance

2 and 3

3.4 - 4.4 

Ω

 [at 25

°

C (77

°

F)]

1 and 2, 3, 4

∞Ω

(Continuity should not exist)

4 and 1, 2, 3