Infiniti Q45 (FY33). Manual - part 139

SEF720X

SEF139P

Generic Scan Tool (GST)

DESCRIPTION

Generic Scan Tool (OBDII scan tool) complying with SAE J1978
has 8 different functions explained on the next page.
ISO9141 is used as the protocol.
The name “GST” or “Generic Scan Tool” is used in this service
manual.

SEF046TA

GST INSPECTION PROCEDURE

Turn off ignition switch.

Connect “GST” to data link connector which is located under
LH dash panel near the hood lock release handle.

IDX

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION

CONSULT-II (Cont’d)

EC-85

SEF398S

Turn ON ignition switch.

Enter the program according to instruction on the screen or in
the operation manual.

(*: Regarding GST screens in this section, sample screens are
shown.)

SEF416S

Perform each diagnostic mode according to each service pro-
cedure.

For further information, see the GST Operation Manual of the
tool maker.

FUNCTION

Diagnostic test mode

Function

MODE 1

READINESS TESTS

This mode gains access to current emission-related data values, including analog
inputs and outputs, digital inputs and outputs, and system status information.

MODE 2

(FREEZE DATA)

This mode gains access to emission-related data value which were stored by ECM
during the freeze frame. [For details, refer to “Freeze Frame Data” (EC-77).]

MODE 3

DTCs

This mode gains access to emission-related power train trouble codes which were
stored by ECM.

MODE 4

CLEAR DIAG INFO

This mode can clear all emission-related diagnostic information. This includes:

Clear number of diagnostic trouble codes (MODE 1)

Clear diagnostic trouble codes (MODE 3)

Clear trouble code for freeze frame data (MODE 1)

Clear freeze frame data (MODE 2)

Reset status of system monitoring test (MODE 1)

Clear on board monitoring test results (MODE 6 and 7)

MODE 6

(ON BOARD TESTS)

This mode accesses the results of on board diagnostic monitoring tests of specific
components/systems that are not continuously monitored.

MODE 7

(ON BOARD TESTS)

This mode enables the off board test drive to obtain test results for emission-related
powertrain components/systems that are continuously monitored during normal driv-
ing conditions.

MODE 8

—

This mode can close EVAP system in ignition switch “ON” position (Engine stopped).
When this mode is performed, the following parts can be opened or closed.

EVAP canister vent control open

Vacuum cut valve bypass valve closed

In the following conditions, this mode cannot function.

Low ambient temperature

Low battery voltage

Engine running

Ignition switch “OFF”

Low fuel temperature

Too much pressure is applied to EVAP system

MODE 9

(CALIBRATION ID)

This mode enables the off-board test device to request specific vehicle information
such as Vehicle Identification Number (VIN) and Calibration IDs.

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION

Generic Scan Tool (GST) (Cont’d)

EC-86

MEF036D

SEF233G

SEF234G

Introduction

The engine has an ECM to control major systems such as fuel
control, ignition control, idle air control system, etc. The ECM
accepts input signals from sensors and instantly drives actuators.
It is essential that both input and output signals are proper and
stable. At the same time, it is important that there are no problems
such as vacuum leaks, fouled spark plugs, or other problems with
the engine.
It is much more difficult to diagnose a problem that occurs intermit-
tently rather than continuously. Most intermittent problems are
caused by poor electric connections or improper wiring. In this
case, careful checking of suspected circuits may help prevent the
replacement of good parts.
A visual check only may not find the cause of the problems. A road
test with CONSULT-II (or GST) or a circuit tester connected should
be performed. Follow the “Work Flow” on EC-89.
Before undertaking actual checks, take just a few minutes to talk
with a customer who approaches with a driveability complaint. The
customer can supply good information about such problems, espe-
cially intermittent ones. Find out what symptoms are present and
under what conditions they occur. A “Diagnostic Worksheet” like the
example below should be used.
Start your diagnosis by looking for “conventional” problems first.
This will help troubleshoot driveability problems on an electronically
controlled engine vehicle.

SEF907L

Diagnostic Worksheet

There are many operating conditions that lead to the malfunctions
of engine components. A good knowledge of such conditions can
make troubleshooting faster and more accurate.
In general, each customer may feel differently about a given prob-
lem. It is important to fully understand the symptoms or conditions
for a customer complaint.
Utilize a diagnostic worksheet like the one shown below in order to
organize all the information for troubleshooting.
Some conditions may cause the malfunction indicator lamp to
come on steady or blink and DTC to be detected. Examples:

Vehicle ran out of fuel, which caused engine misfire.

Fuel filler cap was left off or incorrectly screwed on, allowing
fuel to evaporate into the atmosphere [for models with EVAP
(SMALL LEAK)] diagnosis.

IDX

TROUBLE DIAGNOSIS — Introduction

EC-87

WORKSHEET SAMPLE

Customer name

MR/MS

Model & Year

VIN

Engine #

Trans.

Mileage

Incident Date

Manuf. Date

In Service Date

Fuel and fuel filler cap

Vehicle ran out of fuel causing misfire.

Fuel filler cap was left off or incorrectly screwed on.

Symptoms

Startability

Impossible to start

No combustion

Partial combustion

Partial combustion affected by throttle position

Partial combustion NOT affected by throttle position

Possible but hard to start

Others [

]

Idling

No fast idle

Unstable

High idle

Low idle

Others [

]

Driveability

Stumble

Surge

Knock

Lack of power

Intake backfire

Exhaust backfire

Others [

]

Engine stall

At the time of start

While idling

While accelerating

While decelerating

Just after stopping

While loading

Incident occurrence

Just after delivery

Recently

In the morning

At night

In the daytime

Frequency

All the time

Under certain conditions

Sometimes

Weather conditions

Not affected

Weather

Fine

Raining

Snowing

Others [

]

Temperature

Hot

Warm

Cool

Cold

Humid

°F

Engine conditions

Cold

During warm-up

After warm-up

Engine speed

Road conditions

In town

In suburbs

Highway

Off road (up/down)

Driving conditions

Not affected

At starting

While idling

At racing

While accelerating

While cruising

While decelerating

While turning (RH/LH)

Vehicle speed

Malfunction indicator lamp

Turned on

Not turned on

TROUBLE DIAGNOSIS — Introduction

Diagnostic Worksheet (Cont’d)

EC-88

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