Nissan Frontier. Manual - part 396

P0031, P0032 A/F SENSOR 1 HEATER

EC-155

< DTC/CIRCUIT DIAGNOSIS >

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P0031, P0032 A/F SENSOR 1 HEATER

Description

INFOID:0000000009480786

SYSTEM DESCRIPTION

The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating

condition to keep the temperature of A/F sensor 1 element at the specified range.

On Board Diagnosis Logic

INFOID:0000000009480787

DTC Confirmation Procedure

INFOID:0000000009480788

NOTE:

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and

wait at least 10 seconds before conducting the next test.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is between 10.5V and 16V at

idle.

 WITH CONSULT

1. Start engine and run it for at least 10 seconds at idle speed.

2. Check 1st trip DTC.

3. If 1st trip DTC is detected, go to 

EC-155, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT” above.

Diagnosis Procedure

INFOID:0000000009480789

1.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten two ground screws on the body. Refer to 

EC-149, "Ground Inspection"

.

OK or NG

Sensor

Input Signal to ECM

ECM function

Actuator

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

Engine speed

Air fuel ratio (A/F) sensor 
1 heater control

Air fuel ratio (A/F) sensor 1 
heater

Mass air flow sensor

Amount of intake air

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0031
0031

Air fuel ratio (A/F) sensor 
1 heater control circuit 
low

The current amperage in the air fuel ratio (A/F) 
sensor 1 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM 
through the air fuel ratio (A/F) sensor 1 heater.)

• Harness or connectors

(The A/F sensor 1 heater circuit is 
open or shorted.)

• Air fuel ratio (A/F) sensor 1 heater

P0032
0032

Air fuel ratio (A/F) sensor 
1 heater control circuit 
high

The current amperage in the air fuel ratio (A/F) 
sensor 1 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM 
through the air fuel ratio (A/F) sensor 1 heater.)

• Harness or connectors

(The A/F sensor 1 heater circuit is 
shorted.)

• Air fuel ratio (A/F) sensor 1 heater

BBIA0614E

EC-156

< DTC/CIRCUIT DIAGNOSIS >

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P0031, P0032 A/F SENSOR 1 HEATER

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

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 voltage between A/F sensor 1 terminal 4 and ground with

CONSULT or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E2, F32

• IPDM E/R harness connector E119

• 15A fuse (No.54)

• 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

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check harness continuity between ECM terminal 4 and A/F sensor 1 terminal 3. 

Refer to Wiring Diagram.

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

OK

>> GO TO 5.

NG

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

5.

CHECK A/F SENSOR 1 HEATER

Refer to 

EC-157, "Component Inspection"

.

OK or NG

OK

>> GO TO 6.

NG

>> GO TO 7.

6.

CHECK INTERMITTENT INCIDENT

Perform 

GI-38, "Work Flow"

.

OK or NG

OK

>> GO TO 7.

NG

>> Repair or replace.

7.

REPLACE AIR FUEL RATIO (A/F) SENSOR 1

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

EM-31, "Exploded View"

.

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

lubricant (commercial service tool).

Voltage: Battery voltage

BBIA0617E

Continuity should exist.

P0031, P0032 A/F SENSOR 1 HEATER

EC-157

< DTC/CIRCUIT DIAGNOSIS >

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>> INSPECTION END

Component Inspection

INFOID:0000000009480790

AIR FUEL RATIO (A/F) SENSOR 1 HEATER

Check resistance between terminals 3 and 4.

Check continuity between terminals 3 and 1, 2, terminals 4 and 1, 2.

If NG, replace the 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 Heated Oxygen Sensor

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

cant (commercial service tool).

Resistance: 1.80 - 2.44

Ω [at 25°C (77°F)]

Continuity should not exist.

EC-158

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

P0037, P0038 HO2S2 HEATER

P0037, P0038 HO2S2 HEATER

Description

INFOID:0000000009480791

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

On Board Diagnosis Logic

INFOID:0000000009480792

DTC Confirmation Procedure

INFOID:0000000009480793

NOTE:

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and

wait at least 10 seconds before conducting the next test.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is between 10.5V and 16V at

idle.

 WITH CONSULT

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. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to 

EC-159, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT” above.

Sensor

Input Signal to ECM

ECM Function

Actuator

Camshaft position sensor (PHASE)

Engine speed

Heated oxygen sensor 2 
heater control

Heated oxygen sensor 2 heater

Crankshaft position sensor (POS)

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
0037

Heated oxygen sensor 2 
heater 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
0038

Heated oxygen sensor 2 
heater 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