Infiniti M45 (Y34). Manual - part 448

DTC P1146, P1166 HO2S2

EC-481

DTC P1146, P1166 HO2S2

PFP:226A0

Component Description

ABS002OP

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

ABS002OQ

Specification data are reference values.

On Board Diagnosis Logic

ABS002OR

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 of the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the minimum voltage of sensor is
sufficiently low during the various driving condition such as fuel-cut.

SEF327R

MONITOR ITEM

CONDITION

SPECIFICATION

HO2S2 (B1)
HO2S2 (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.

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

SEF972Z

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1146
1146
(Bank 1)

Heated oxygen sensor 2
minimum voltage monitoring

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

●

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

●

Heated oxygen sensor 2

●

Fuel pressure

●

Fuel injector

P1166
1166
(Bank 2)

EC-482

DTC P1146, P1166 HO2S2

DTC Confirmation Procedure

ABS002OS

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.

WITH CONSULT-II

TESTING CONDITION:
For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30

C (32 to 86

F).

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

Start engine and warm it up to the normal operating tempera-
ture.

Turn ignition switch OFF and wait at least 10 seconds.

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

Let engine idle for 1 minute.

Make sure that “COOLAN TEMP/S” indicates more than 70

(158

F).

If not, warm up engine and go to next step when “COOLAN
TEMP/S” indication reaches to 70

C (158

F).

Open engine hood.

Select “HO2S2 (B1) P1146” or “HO2S2 (B2) P1166” of “HO2S2” in “DTC WORK SUPPORT” mode with
CONSULT-II.

Start engine and following the instruction of CONSULT-II.

10. Make sure that “OK” is displayed after touching “SELF-DIAG RESULTS”.

If “NG” is displayed, refer to

EC-488, "Diagnostic Procedure"

If “CAN NOT BE DIAGNOSED” is displayed, perform the following.

Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).

Return to step 1.

Overall Function Check

ABS002OT

Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st
trip DTC might not be confirmed.

WITH GST

Start engine and warm it up to the normal operating temperature.

Turn ignition switch OFF and wait at least 10 seconds.

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

Let engine idle for 1 minute.

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

SEF189Y

PBIB0818E

DTC P1146, P1166 HO2S2

EC-483

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 below 0.48V at least once during this
procedure.
If the voltage can be confirmed in step 6, step 7 is not nec-
essary.

Keep vehicle at idling for 10 minutes, then check the 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.

If NG, go to

EC-488, "Diagnostic Procedure"

PBIB2079E

EC-484

DTC P1146, P1166 HO2S2

Wiring Diagram

ABS002OU

BANK 1

TBWA0276E

Content .. 446 447 448 449 ..