Content .. 170 171 172 173 ..

Infiniti Q45 (FY33). Manual - part 172

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

INSPECTION END

SEC033C

SEF354WA

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

IDX

TROUBLE DIAGNOSIS FOR DTC P0137 (B1), P0157 (B2)

Heated Oxygen Sensor 2 (Rear) (P0137: Bank
1), (P0157: Bank 2) (Min. Voltage Monitoring)
(Cont’d)

EC-217

SEF327R

Heated Oxygen Sensor 2 (Rear) (P0138: Bank
1), (P0158: Bank 2) (Max. Voltage Monitoring)

COMPONENT DESCRIPTION

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

CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE

Specification data are reference values.

MONITOR ITEM

CONDITION

SPECIFICATION

HO2S1 (B1)
HO2S1 (B2)

Engine: After warming up

Revving engine from idle up to 2,000
rpm

0 - 0.3V

)

0.6 - 1.0V

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)

90 (B1)

Heated oxygen sensor 2
(rear)

Engine is running.

After warming up to normal operating tempera-
ture and revving engine from idle up to 2,000
rpm.

0 - Approximately 1.0V

89 (B2)

SEF303UA

ON BOARD DIAGNOSIS LOGIC

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

TROUBLE DIAGNOSIS FOR DTC P0138 (B1), P0158 (B2)

EC-218

Diagnostic Trouble

Code No.

Malfunction is detected when ...

Check Items

(Possible Cause)

P0138 (B1)
0510
(Bank 1)

The maximum 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 (rear)

Fuel pressure

Injectors

Intake air leaks

P0158 (B2)
0313
(Bank 2)

SEC034C

SEC035C

SEC036C

SEC037C

DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE

CAUTION:

Always drive vehicle at a safe speed.
NOTE:

“COMPLETED” will appear on CONSULT-II screen when all
tests “COND1”, “COND2” and “COND3” are completed.

If “DIAGNOSTIC TROUBLE CODE CONFIRMATION PRO-
CEDURE” has been previously conducted, always turn
ignition switch “OFF” and wait at least 5 seconds before
conducting the next test.

TESTING CONDITION:
Never stop engine during this test. If the engine is stopped,
reperform this test from step 2).

Procedure for COND1

1) Start engine and warm it up to normal operating tem-

perature.

2) Turn ignition switch “OFF” and wait at least 5 seconds.
3) Turn ignition switch “ON” and select “HO2S2 (B1)

P0138, (B2) P0158” of “HO2S2” in “DTC WORK SUP-
PORT” mode with CONSULT-II.

4) Touch “START”.
5) Start engine (TCS switch “OFF”) and let it idle for at

least 30 seconds.

6) Rev engine to 2,000 rpm 2 or 3 times quickly under no

load.
If “COMPLETED” appears on CONSULT-II screen, go
to step 10).
If “COMPLETED” does not appear on CONSULT-II
screen, go to the following step.

7) Drive vehicle at a speed of more than 70 km/h (43 MPH)

for 2 consecutive minutes.

8) When the following conditions are met, “TESTING” will

be displayed at “COND1” on the CONSULT-II screen.
Maintain the conditions continuously until “TESTING”
changes to “COMPLETED”. (It will take approximately
60 seconds.)
CMPS-RPM (POS): 1,200 - 2,500 rpm
Vehicle speed: 64 - 100 km/h (40 - 62 MPH)
B/FUEL SCHDL: 0.5 - 5.0 msec
Selector lever: Suitable position

NOTE:

If “TESTING” is not displayed after 5 minutes, retry
from step 2).

If “COMPLETED” already appears at “COND2” on
CONSULT-II screen before “Procedure for COND2”
is conducted, it is unnecessary to conduct step 9).

IDX

TROUBLE DIAGNOSIS FOR DTC P0138 (B1), P0158 (B2)

Heated Oxygen Sensor 2 (Rear) (P0138: Bank
1), (P0158: Bank 2) (Max. Voltage Monitoring)
(Cont’d)

EC-219

SEF665Y

Procedure for COND2
9) While driving, release accelerator pedal completely with

“OD” OFF from the above condition [step 8] until
“INCOMPLETE” at “COND2” on CONSULT-II screen is
turned to “COMPLETED”. (It will take approximately 4
seconds.)

NOTE:
If “COMPLETED” is already appears at “COND3” on
CONSULT-II screen before “Procedure for COND3” is
conducted, it is unnecessary to conduct step 10).
Procedure for COND3
10) Stop vehicle and let it idle until “INCOMPLETE” of

“COND3” on CONSULT-II screen has turned to “COM-
PLETED”. (It will take maximum of approximately 6 min-
utes.)

11) Make sure that “OK” is displayed after touching “SELF-

DIAG RESULTS”. If “NG” is displayed, refer to “DIAG-
NOSTIC PROCEDURE”, EC-223.

SEF354WA

OVERALL FUNCTION CHECK

Use this procedure to check the overall function of the heated oxy-
gen sensor 2 (rear) circuit. During this check, a 1st trip DTC might
not be confirmed.

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 revving engine 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
during this procedure.
If the voltage can be confirmed in 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 above 0.48V at least once
during this procedure.

6) If NG, go to “DIAGNOSTIC PROCEDURE”, EC-223.

TROUBLE DIAGNOSIS FOR DTC P0138 (B1), P0158 (B2)

Heated Oxygen Sensor 2 (Rear) (P0138: Bank
1), (P0158: Bank 2) (Max. Voltage Monitoring)
(Cont’d)

EC-220

Content .. 170 171 172 173 ..