Infiniti I30 (A33). Manual — part 244

6

CHECK INTERMITTENT INCIDENT

Refer to “TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT”, EC-144.

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INSPECTION END

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DTC P0141 (BANK 1), P0161 (BANK 2) HO2S2 HEATER (REAR)

Diagnostic Procedure (Cont’d)

EC-291

On Board Diagnosis Logic

NHEC0169

With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1 (front).
The ECM calculates the necessary compensation to correct the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).

Sensor

Input Signal to ECM

ECM func-

tion

Actuator

Heated oxygen sensors 1 (front)

Density of oxygen in exhaust gas
(Mixture ratio feedback signal)

Fuel injec-
tion control

Injectors

Malfunction is detected when fuel injection system does not operate properly, the amount of mixture ratio
compensation is too large.
(The mixture ratio is too lean.)

Possible Cause

NHEC0487

I

Intake air leaks

I

Heated oxygen sensor 1 (front)

I

Injectors

I

Exhaust gas leaks

I

Incorrect fuel pressure

I

Lack of fuel

I

Mass air flow sensor

SEF215Z

DTC Confirmation Procedure

NHEC0170

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

NHEC0170S01

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 “SELF-LEARNING CONT”
in “WORK SUPPORT” mode with CONSULT-II.

4)

Clear the self-learning control coefficient by touching “START”.

5)

Select “DATA MONITOR” mode with CONSULT-II.

6)

Start engine again and let it idle for at least 10 minutes.
The 1st trip DTC P0171 or P0174 should be detected at this
stage, if a malfunction exists. If so, go to “Diagnostic
Procedure”, EC-296.

7)

If it is difficult to start engine at step 6, the fuel injection sys-
tem has a malfunction, too.

8)

Crank engine while depressing accelerator pedal. If engine
starts, go to “Diagnostic Procedure”, EC-296. If engine does
not start, check exhaust and intake air leak visually.

DTC P0171 (BANK 1), P0174 (BANK 2) FUEL INJECTION SYSTEM FUNCTION

(LEAN)

On Board Diagnosis Logic

EC-292

SEF256X

WITH GST

NHEC0170S02

1)

Start engine and warm it up to normal operating temperature.

2)

Turn ignition switch “OFF” and wait at least 10 seconds.

3)

Disconnect mass air flow sensor harness connector. Then
restart and run engine for at least 5 seconds at idle speed.

4)

Stop engine and reconnect mass air flow sensor harness con-
nector.

5)

Select “MODE 7” with GST. Make sure 1st trip DTC P0100 is
detected.

6)

Select “MODE 4” with GST and erase the 1st trip DTC P0100.

7)

Start engine again and let it idle for at least 10 minutes.

8)

Select “MODE 7” with GST. The 1st trip DTC P0171 or P0174
should be detected at this stage, if a malfunction exists. If so,
go to “Diagnostic Procedure”, EC-296.

9)

If it is difficult to start engine at step 7, the fuel injection sys-
tem has a malfunction.

10) Crank engine while depressing accelerator pedal. If engine

starts, go to “Diagnostic Procedure”, EC-296. If engine does
not start, check exhaust and intake air leak visually.

GI

MA

EM

LC

FE

AT

AX

SU

BR

ST

RS

BT

HA

SC

EL

IDX

DTC P0171 (BANK 1), P0174 (BANK 2) FUEL INJECTION SYSTEM FUNCTION

(LEAN)

DTC Confirmation Procedure (Cont’d)

EC-293

Wiring Diagram

NHEC0171

BANK 1

NHEC0171S01

MEC416D

DTC P0171 (BANK 1), P0174 (BANK 2) FUEL INJECTION SYSTEM FUNCTION

(LEAN)

Wiring Diagram

EC-294