Content .. 175 176 177 178 ..

Infiniti Q45 (FY33). Manual - part 177

SEF055TA

SEF377U

SEC032C

SEF398UA

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DIAGNOSTIC PROCEDURE

INSPECTION START

1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground screws.

CHECK INPUT SIGNAL CIRCUIT.
1. Disconnect heated oxygen sensor 2 (rear)

harness connector and ECM harness connec-
tor.

2. Check harness continuity between ECM and

sensor terminals.

Continuity should exist.

3. Check harness continuity between ECM sen-

sor or ground terminals.

Continuity should not exist.

If OK, check harness for short to ground and
short to power.

Check the following.

Harness connectors

E12

(B1) or

F14

F131

(B2)

Harness connectors

E19

E102

(B1)

If NG, repair open circuit or
short to ground or short to
power in harness or connec-
tors.

CHECK GROUND CIRCUIT.
Check harness continuity between terminal

and engine ground.
Continuity should exist.
If OK, check harness for short to power.

Check the following.

Harness connectors

E12

(B1) or

F14

F131

(B2)

Harness connectors

E19

E102

(B1)

Harness connectors

F62

F61

Harness for open or short
between heated oxygen sen-
sor 2 (rear) and engine
ground

If NG, repair open circuit or
short to power in harness or
connectors.

CHECK COMPONENT
[Heated oxygen sensor 2 (rear)].
1. Turn ignition switch “OFF”.

2. Disconnect sensor harness connector and

check for water.
Water should not exist.
If OK, go to step 3.

3. Check heated oxygen sensor 2 (rear).
Refer to “COMPONENT INSPECTION” on next
page.

Repair or replace harness
and/or connectors or replace
corresponding heated oxygen
sensor.

Perform “TROUBLE DIAGNOSIS FOR INTER-
MITTENT INCIDENT”, EC-117.

INSPECTION END

DTC

Terminals

Bank

(Harness

protector

color)

ECM

Sensor

P0140

(B1) (White)

P0160

(B2) (Red)

DTC

Terminals

Bank

(Harness

protector

color)

ECM or

sensor

Ground

P0140

90 or 2

Ground

(B1) (White)

P0160

89 or 2

Ground

(B2) (Red)

IDX

TROUBLE DIAGNOSIS FOR DTC P0140 (B1), P0160 (B2)

Heated Oxygen Sensor 2 (Rear) (P0140: Bank
1), (P0160: Bank 2) (High voltage) (Cont’d)

EC-237

SEC033C

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COMPONENT INSPECTION

Heated oxygen sensor 2 (rear)

1) Start engine and drive vehicle at a speed of more than

70 km/h (43 MPH) for 2 consecutive minutes.

2) Stop vehicle with engine running.
3) Select “FUEL INJECTION” in “ACTIVE TEST” mode,

and select “HO2S2 (B1) (B2)” as the monitor item with
CONSULT-II.

4) Check “HO2S2 (B1) (B2)” at idle speed when adjusting

“FUEL INJECTION” to ±25%.
“HO2S2 (B1) (B2)” should be above 0.48V at least
once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1) (B2)” should be below 0.43V at least
once when the “FUEL INJECTION” is −25%.

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ OR ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

1) Start engine and drive vehicle at a speed of more than

70 km/h (43 MPH) for 2 consecutive minutes.

2) Stop vehicle with engine running.
3) Set voltmeter probes between ECM terminals

(B2),

(B1) (sensor signal) and ground.

4) Check the voltage when racing up to 4,000 rpm under

no load at least 10 times.
(depress and release accelerator pedal as soon as pos-
sible)
The voltage should be above 0.48V at least once.
If the voltage is above 0.48V at step 4, step 5 is not
necessary.

5) 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 with “OD” OFF.
The voltage should be below 0.43V at least once.

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 sys-
tem threads using Oxygen Sensor Thread Cleaner tool
J-43897-18 or J-43897-12 and approved anti-seize lubri-
cant.

SEF244Y

TROUBLE DIAGNOSIS FOR DTC P0140 (B1), P0160 (B2)

Heated Oxygen Sensor 2 (Rear) (P0140: Bank
1), (P0160: Bank 2) (High voltage) (Cont’d)

EC-238

Heated Oxygen Sensor 2 Heaters (Rear)
(P0141: Bank 1), (P0161: Bank 2)

SYSTEM DESCRIPTION

Camshaft position sensor

Engine speed

ECM

Heated
oxygen
sensor 2
heater
(rear)

Mass air flow sensor

Amount of intake air

The ECM performs ON/OFF control of the heated
oxygen sensor 2 heater (rear) corresponding to the
engine speed.

OPERATION

Engine speed rpm

Heated oxygen sensor 2

heater (rear)

Ignition switch “ON” (Engine

stopped)

OFF

At idle [after driving for 2 min-

utes at a speed of more than

70 km/h (43 MPH)]

CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE

Specification data are reference values.

MONITOR ITEM

CONDITION

SPECIFICATION

HO2S2 HTR (B1)
HO2S2 HTR (B2)

Engine speed: At idle [after driving for 2 minutes at a speed of more than 70
km/h (43 MPH)]

Engine speed: Above 3,600 rpm

Ignition “ON” with engine stopped

OFF

ECM TERMINALS AND REFERENCE VALUE

Specification data are reference values, and are measured between each terminal and ground.

CAUTION:

Do not use ECM ground terminals when measuring voltage. Doing so may result in damage to the
ECM’s transistor. Use a ground other than ECM terminals such as the body ground.

TER-

MINAL

NO.

WIRE

COLOR

ITEM

CONDITION

DATA

(DC voltage)

18
19

Y/R
L

Heated oxygen sensor 2
heater (rear) (B1)
Heated oxygen sensor 2
heater (rear) (B2)

Engine is running.

At idle [after driving 2 minutes at 70 km/h (43
MPH) or more]

0 - 0.5V

Ignition switch “ON”

Engine stopped

Engine is running.

Engine speed is above 3,600 rpm.

BATTERY VOLTAGE
(11 - 14V)

IDX

TROUBLE DIAGNOSIS FOR DTC P0141 (B1), P0161 (B2)

EC-239

ON BOARD DIAGNOSIS LOGIC

Diagnostic Trouble

Code No.

Malfunction is detected when ....

Check Items

(Possible Cause)

P0141
0902
(B1)

The current amperage in the heated oxygen sensor
2 heater (rear) circuit is out of the normal range.
[The improper voltage drop signal is sent to ECM
through the heated oxygen sensor 2 heater (rear).]

Harness or connectors
[The heated oxygen sensor 2 heater (rear) circuit is
open or shorted.]

Heated oxygen sensor 2 heater (rear)

P0161
1002
(B2)

SEF261Y

DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE

NOTE:
If “DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCE-
DURE” has been previously conducted, always turn ignition
switch “OFF” and wait at least 5 seconds before conducting
the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that bat-
tery voltage is more than 10.5V.

1) Turn ignition switch “ON” and select “DATA MONITOR”

mode with CONSULT-II.

2) Start engine and drive vehicle at a speed of more than

70 km/h (43 MPH) for 2 consecutive minutes.

3) If 1st trip DTC is detected, go to “DIAGNOSTIC

PROCEDURE”, EC-243.

1) Start engine and drive vehicle at a speed of more than

70 km/h (43 MPH) for 2 consecutive minutes.

2) Turn ignition switch “OFF” and wait at least 5 seconds.
3) Start engine and drive vehicle at a speed of more than

70 km/h (43 MPH) for 2 consecutive minutes.

4) Select “MODE 3” with GST.
5) If

DTC

detected,

“DIAGNOSTIC

PROCEDURE”, EC-243.

When using GST, “DIAGNOSTIC TROUBLE CODE CONFIRMA-
TION PROCEDURE” should be performed twice as much as
when using CONSULT-II because GST cannot display MODE 7
(1st trip DTC) concerning this diagnosis. Therefore, using
CONSULT-II is recommended.

TROUBLE DIAGNOSIS FOR DTC P0141 (B1), P0161 (B2)

Heated Oxygen Sensor 2 Heaters (Rear)
(P0141: Bank 1), (P0161: Bank 2) (Cont’d)

EC-240

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