Infiniti I35 (A33). Manual - part 188

MIL illuminates in diagnostic test mode II (SELF-DIAGNOSTIC RESULTS), it is a DTC; if two or more codes
are displayed, they may be either DTCs or 1st trip DTCs. DTC No. is same as that of 1st trip DTC. These
unidentified codes can be identified by using the CONSULT-II or GST. A DTC will be used as an example for
how to read a code.

SEF952W

A particular trouble code can be identified by the number of four-digit numeral flashes. The “zero” is indicated
by the number of ten flashes. The length of time the 1,000th-digit numeral flashes on and off is 1.2 seconds
consisting of an ON (0.6-second) - OFF (0.6-second) cycle.
The 100th-digit numeral and lower digit numerals consist of a 0.3-second ON and 0.3-second OFF cycle.
A change from one digit numeral to another occurs at an interval of 1.0-second OFF. In other words, the later
numeral appears on the display 1.3 seconds after the former numeral has disappeared.
A change from one trouble code to another occurs at an interval of 1.8-second OFF.
In this way, all the detected malfunctions are classified by their DTC numbers. The DTC 0000 refers to no
malfunction. (See “TROUBLE DIAGNOSIS — INDEX”, EC-9.)

How to Erase Diagnostic Test Mode II (Self-diagnostic Results)

NHEC1189S0601

The DTC can be erased from the back up memory in the ECM by depressing accelerator pedal. Refer to How
to Switch Diagnostic Test Mode.

If the battery is disconnected, the DTC will be lost from the backup memory within 24 hours.

Be careful not to erase the stored memory before starting trouble diagnoses.

DIAGNOSTIC TEST MODE II — HEATED OXYGEN SENSOR 1 MONITOR

NHEC1189S07

In this mode, the MIL displays the condition of the fuel mixture (lean or rich) which is monitored by the heated
oxygen sensor 1.

MIL

Fuel mixture condition in the exhaust gas

Air fuel ratio feedback control condition

Lean

Closed loop system

OFF

Rich

*Remains ON or OFF

Any condition

Open loop system

*: Maintains conditions just before switching to open loop.

To check the heated oxygen sensor 1 function, start engine in the Diagnostic Test Mode II and warm it up until
engine coolant temperature indicator points to the middle of the gauge.
Next run engine at about 2,000 rpm for about 2 minutes under no-load conditions. Then make sure that the
MIL comes ON more than 5 times within 10 seconds with engine running at 2,000 rpm under no-load.

IDX

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION

Malfunction Indicator Lamp (MIL) (Cont’d)

EC-93

OBD System Operation Chart

NHEC0033

RELATIONSHIP BETWEEN MIL, 1ST TRIP DTC, DTC, AND DETECTABLE ITEMS

NHEC0033S01

When a malfunction is detected for the first time, the 1st trip DTC and the 1st trip freeze frame data are
stored in the ECM memory.

When the same malfunction is detected in two consecutive trips, the DTC and the freeze frame data are
stored in the ECM memory, and the MIL will come on. For details, refer to “Two Trip Detection Logic” on
EC-74.

The MIL will go off after the vehicle is driven 3 times with no malfunction. The drive is counted only when
the recorded driving pattern is met (as stored in the ECM). If another malfunction occurs while counting,
the counter will reset.

The DTC and the freeze frame data will be stored until the vehicle is driven 40 times (driving pattern A)
without the same malfunction recurring (except for Misfire and Fuel Injection System). For Misfire and Fuel
Injection System, the DTC and freeze frame data will be stored until the vehicle is driven 80 times (driv-
ing pattern C) without the same malfunction recurring. The “TIME” in “SELF-DIAGNOSTIC RESULTS”
mode of CONSULT-II will count the number of times the vehicle is driven.

The 1st trip DTC is not displayed when the self-diagnosis results in “OK” for the 2nd trip.

SUMMARY CHART

NHEC0033S02

Items

Fuel Injection System

Misfire

Other

MIL (goes off)

3 (pattern B)

DTC, Freeze Frame Data (no
display)

80 (pattern C)

40 (pattern A)

1st Trip DTC (clear)

1 (pattern C), *1

1 (pattern B)

1st Trip Freeze Frame Data
(clear)

*1, *2

1 (pattern B)

For details about patterns B and C under “Fuel Injection System” and “Misfire”, see EC-96.
For details about patterns A and B under “Other”, see EC-98.
*1: Clear timing is at the moment OK is detected.
*2: Clear timing is when the same malfunction is detected in the 2nd trip.

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION

OBD System Operation Chart

EC-94

RELATIONSHIP BETWEEN MIL, DTC, 1ST TRIP DTC AND DRIVING PATTERNS FOR
“MISFIRE” <EXHAUST QUALITY DETERIORATION>, “FUEL INJECTION SYSTEM”

=NHEC0033S03

SEF392S

*1: When the same malfunction is

detected in two consecutive trips,
MIL will light up.

*2: MIL will go off after vehicle is

driven 3 times (pattern B) without
any malfunctions.

*3: When the same malfunction is

detected in two consecutive trips,
the DTC and the freeze frame
data will be stored in ECM.

*4: The DTC and the freeze frame

data will not be displayed any
longer after vehicle is driven 80
times (pattern C) without the same
malfunction. (The DTC and the
freeze frame data still remain in
ECM.)

*5: When a malfunction is detected

for the first time, the 1st trip DTC
and the 1st trip freeze frame data
will be stored in ECM.

*6: The 1st trip DTC and the 1st trip

freeze frame data will be cleared
at the moment OK is detected.

*7: When the same malfunction is

detected in the 2nd trip, the 1st
trip freeze frame data will be
cleared.

*8: 1st trip DTC will be cleared when

vehicle is driven once (pattern C)
without the same malfunction after
DTC is stored in ECM.

IDX

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION

OBD System Operation Chart (Cont’d)

EC-95

EXPLANATION FOR DRIVING PATTERNS FOR “MISFIRE <EXHAUST QUALITY
DETERIORATION>”, “FUEL INJECTION SYSTEM”

NHEC0033S04

<Driving Pattern B>

NHEC0033S0401

Driving pattern B means the vehicle operation as follows:
All components and systems should be monitored at least once by the OBD system.

The B counter will be cleared when the malfunction is detected once regardless of the driving pattern.

The B counter will be counted up when driving pattern B is satisfied without any malfunction.

The MIL will go off when the B counter reaches 3. (*2 in “OBD SYSTEM OPERATION CHART”)

<Driving Pattern C>

NHEC0033S0402

Driving pattern C means the vehicle operation as follows:
1) The following conditions should be satisfied at the same time:

Engine speed: (Engine speed in the freeze frame data)

375 rpm

Calculated load value: (Calculated load value in the freeze frame data) x (1

0.1) [%]

Engine coolant temperature (T) condition:

When the freeze frame data shows lower than 70°C (158°F), T should be lower than 70°C (158°F).

When the freeze frame data shows higher than or equal to 70°C (158°F), T should be higher than or equal
to 70°C (158°F).

Example:
If the stored freeze frame data is as follows:
Engine speed: 850 rpm, Calculated load value: 30%, Engine coolant temperature: 80°C (176°F)
To be satisfied with driving pattern C, the vehicle should run under the following conditions:
Engine speed: 475 - 1,225 rpm, Calculated load value: 27 - 33%, Engine coolant temperature: more than 70°C
(158°F)

The C counter will be cleared when the malfunction is detected regardless of (1).

The C counter will be counted up when (1) is satisfied without the same malfunction.

The DTC will not be displayed after C counter reaches 80.

The 1st trip DTC will be cleared when C counter is counted once without the same malfunction after DTC
is stored in ECM.

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION

OBD System Operation Chart (Cont’d)

EC-96

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