Infiniti F50. Manual - part 461

DTC P1146, P1166 HO2S2

EC-485

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EC

5. 

CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Disconnect ECM harness connector.

2.

Check harness continuity between ECM terminal and HO2S2 terminal as follows.
Refer to Wiring Diagram.

3.

Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.

4.

Also check harness for short to ground or short to short to power.

OK or NG

OK

>> GO TO 7.

NG

>> GO TO 6.

6. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors E315, F5

●

Harness open or short between HO2S2 and ECM

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

7. 

CHECK HEATED OXYGEN SENSOR 2

Refer to 

EC-485, "Component Inspection"

 .

OK or NG

OK

>> GO TO 8.

NG

>> Replace malfunctioning heated oxygen sensor 2.

8. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-132, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

EBS00MJ3

HEATED OXYGEN SENSOR 2

 With CONSULT-II

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 engine speed between 3,500 and 4,000 rpm for one minute under no load.

4.

Let engine idle for one minute.

DTC

Terminals

Bank

ECM

Sensor

P1146

123

1

1

P1166

124

1

2

Continuity should exist.

DTC

Terminals

Bank

ECM

Sensor

P1146

123

1

1

P1166

124

1

2

Continuity should not exist.

EC-486

DTC P1146, P1166 HO2S2

5.

Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select
“HO2S2 (B1)/(B2)” as the monitor item with CONSULT-II.

6.

Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to 

±

25%.

“HO2S2 (B1)/(B2)” should be above 0.58V at least once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1)/(B2)” should be below 0.48V at least once when the “FUEL INJECTION” is 

−

25%.

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.

 Without CONSULT-II

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 engine speed between 3,500 and 4,000 rpm for 1 minute under no load.

4.

Let engine idle for 1 minute.

5.

Set voltmeter probes between ECM terminal 123 [HO2S2 (B1) signal] or 124 [HO2S2 (B2) signal] and
engine ground.

6.

Check the voltage when revving up to 4,000 rpm under no load
at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
The voltage should be above 0.58V at least once during this
procedure.
If the voltage is above 0.58V at step 6, step 7 is not neces-
sary.

7.

Keep vehicle at idling for 10 minutes, then check voltage. Or
check the voltage when coasting from 80 km/h (50 MPH) in “D”
position.
The voltage should be below 0.48V at least once during this
procedure.

8.

If NG, replace 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.

PBIB1918E

PBIB1153E

PBIB0068E

DTC P1146, P1166 HO2S2

EC-487

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Removal and Installation

EBS00MJ4

HEATED OXYGEN SENSOR 2

Refer to 

EM-22, "EXHAUST MANIFOLD AND THREE WAY CATALYST"

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EC-488

DTC P1147, P1167 HO2S2

DTC P1147, P1167 HO2S2

PFP:226A0

Component Description

EBS00MJ5

The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the heated oxygen sensor 1 are
shifted, the air-fuel ratio is controlled to stoichiometric, by the signal
from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.

CONSULT-II Reference Value in Data Monitor Mode

EBS00MJ6

Specification data are reference values.

On Board Diagnosis Logic

EBS00MJ7

The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the heated oxygen sensor 1. The oxygen
storage capacity before the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the maximum voltage of the sensor
is sufficiently high during the various driving condition such as fuel-
cut.

SEF327R

MONITOR ITEM

CONDITION

SPECIFICATION

HO2S2 (B1)
HO2S2 (B2)

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Warm-up condition

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After keeping the engine speed 
between 3,500 and 4,000 rpm for 1 
minute and at idle for 1 minute 
under no load

Revving engine from idle up to 
3,000 rpm quickly.

0 - 0.3V 

←→

 Approx. 0.6 - 1.0V

HO2S2 MNTR (B1)
HO2S2 MNTR (B2)

●

Warm-up condition

●

After keeping the engine speed 
between 3,500 and 4,000 rpm for 1 
minute and at idle for 1 minute 
under no load

Revving engine from idle up to 
3,000 rpm quickly.

LEAN 

←→

 RICH

PBIB1154E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1147
1147
(Bank 1)

Heated oxygen sensor 2 
maximum voltage monitoring

The maximum voltage from the sensor is 
not reached to the specified voltage.

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Harness or connectors
(The sensor circuit is open or shorted)

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Heated oxygen sensor 2

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Fuel pressure

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Injectors

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Intake air leaks

P1167
1167
(Bank 2)