Infiniti QX56 (JA60). Manual - part 361

EC-96

< COMPONENT DIAGNOSIS >

[VK56DE]

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

Refer to 

EC-85, "Ground Inspection"

.

OK or NG

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-III or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E5, F14

• IPDM E/R harness connector E119

• 15 A 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 2 (bank 1) or 24, 43 (bank 2) and A/F sensor 1 terminal

3.

Refer to Wiring Diagram.

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

BBIA0354E

 Voltage: Battery voltage

BBIA0376E

PBIB3308E

Continuity should exist.

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

EC-97

< COMPONENT DIAGNOSIS >

[VK56DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

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 A/F SENSOR 1 HEATER

Refer to 

EC-97, "Component Inspection"

.

OK or NG

OK

>> GO TO 6.

NG

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

6.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-35, "How to Check Terminal"

 and 

GI-38, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000005149099

AIR FUEL RATIO (A/F) SENSOR 1 HEATER

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

2. If NG, replace air fuel ratio (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 tool J-

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

Terminal No.

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

PBIB3309E

EC-98

< COMPONENT DIAGNOSIS >

[VK56DE]

P0037, P0038, P0057, P0058 HO2S2 HEATER

P0037, P0038, P0057, P0058 HO2S2 HEATER

Description

INFOID:0000000005149100

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:0000000005149101

DTC Confirmation Procedure

INFOID:0000000005149102

NOTE:

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting the next step.

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 10.5V and 16V at

idle.
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 the engine and keep the engine speed between 3,500 rpm and 4,000 rpm for at least 1 minute under

no load.

5. Let engine idle for 1 minute.

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
0037
(Bank 1)

Heated oxygen sensor 2 
heater 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

P0057
0057
(Bank 2)

P0038
0038
(Bank 1)

Heated oxygen sensor 2 
heater 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

P0058
0058
(Bank 2)

P0037, P0038, P0057, P0058 HO2S2 HEATER

EC-99

< COMPONENT DIAGNOSIS >

[VK56DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

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

EC-99, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005149103

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.

NG

>> Repair or replace ground connections.

2.

CHECK HO2S2 POWER SUPPLY CIRCUIT

1. Disconnect heated oxygen sensor 2 harness connector.

2. Turn ignition switch ON.

3. Check voltage between HO2S2 terminal 3 and ground with

CONSULT-III or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E5, F14

• IPDM E/R harness connector E119

• 15 A fuse (No. 54)

• Harness for open or short between heated oxygen sensor 2 and fuse

>> Repair harness or connectors.

4.

CHECK HO2S2 HEATER OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

BBIA0354E

BBIA0435E

Voltage: Battery voltage

PBIB0112E