Infiniti M45 (Y34). Manual - part 367

DTC P0031, P0032, P0051, P0052 HO2S1 HEATER

EC-157

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DTC P0031, P0032, P0051, P0052 HO2S1 HEATER

PFP:22690

Description

ABS002EK

SYSTEM DESCRIPTION

The ECM performs ON/OFF control of the heated oxygen sensor 1 heater corresponding to the engine speed
and engine coolant temperature. The duty percent varies with engine coolant temperature when engine is
started.

OPERATION

CONSULT-II Reference Value in Data Monitor Mode

ABS002EL

Specification data are reference values.

On Board Diagnosis Logic

ABS002EM

Sensor

Input Signal to ECM

ECM function

Actuator

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

Engine speed

Heated oxygen sensor 1 
heater control

Heated oxygen sensor 1 heater

Engine coolant temperature sensor

Engine coolant temperature

Engine speed rpm

Heated oxygen sensor 1 heater

Above 3,000

OFF

Below 3,000 after warming up

ON

MONITOR ITEM

CONDITION

SPECIFICATION

HO2S1 HTR (B1)
HO2S1 HTR (B2)

●

Engine: After warming up

●

Engine speed: Below 3,000 rpm

ON

●

Engine speed: Above 3,000 rpm

OFF

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0031
0031
(Bank 1)

Heated oxygen sensor 1 
heater control circuit low

The current amperage in the heated oxygen sensor 
1 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM 
through the heated oxygen sensor 1 heater.)

●

Harness or connectors
(The heated oxygen sensor 1 heater 
circuit is open or shorted.)

●

Heater oxygen sensor 1 heater

P0051
0051
(Bank 2)

P0032
0032
(Bank 1)

Heated oxygen sensor 1 
heater control circuit high

The current amperage in the heated oxygen sensor 
1 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM 
through the heated oxygen sensor 1 heater.)

●

Harness or connectors
(The heated oxygen sensor 1 heater 
circuit is shorted.)

●

Heater oxygen sensor 1 heater

P0052
0052
(Bank 2)

EC-158

DTC P0031, P0032, P0051, P0052 HO2S1 HEATER

DTC Confirmation Procedure

ABS002EN

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-II

1.

Start engine and warm it up to normal operating temperature. 

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.

4.

Start engine and let it idle for at least 6 seconds.

5.

If 1st trip DTC is detected, go to 

EC-162, "Diagnostic Procedure"

.

 WITH GST

1.

Start engine and warm it up to normal operating temperature. 

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and let it idle for at least 6 seconds.

4.

Turn ignition switch OFF and wait at least 10 seconds.

5.

Start engine and let it idle for at least 6 seconds.

6.

Select “MODE 3” with GST.

7.

If DTC is detected, go to 

EC-162, "Diagnostic Procedure"

 .

●

When using GST, DTC Confirmation Procedure should be performed twice as much as when
using CONSULT-II because GST cannot display MODE 7 (1st trip DTC) concerning this diagno-
sis. Therefore, using CONSULT-II is recommended.

SEF174Y

DTC P0031, P0032, P0051, P0052 HO2S1 HEATER

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Wiring Diagram

ABS002EO

BANK 1

TBWA0267E

EC-160

DTC P0031, P0032, P0051, P0052 HO2S1 HEATER

Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

8

BR

Heated oxygen sensor 1 
heater (bank 1)

[Engine is running]

●

Warm-up condition

●

Engine speed: Below 3,000 rpm.

Approximately 7V

[Engine is running]

●

Engine speed: Above 3,000 rpm.

BATTERY VOLTAGE
(11 - 14V)

PBIB0519E