display ISUZU AXIOM 2002 Service Owner's Manual

5A±36BRAKE CONTROL SYSTEM
Diagnosis By ªABSº Warning Light
Illumination Pattern
In the event that there is abnormality in the ªABSº warning
light illumination pattern while the key is in the ON position
or if the warning light is actuated while driving, refer to the
flow chart below for the correct diagnostic procedure.
No.
ConditionªABSº Warning Light Illumination PatternDiagnostic
1Warning light is
actuated normallyNormal
2Warning light is not litWarning light lighting circuit
trouble"Go to Chart B-1
3Warning light remains
ONDiagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.
4Warning light is
actuated while drivingDiagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.
5Warning light goes at
12 km/h (8 mph) or
higher (After repairing
the faulty part)Even after repairing the
faulty part the warning light
(W/L) dose not go out if
vehicle is at a stop.
Turn the ignition switch to the
ON position and drive the
vehicle at 12 km/h (8 mph) or
higher to make sure that the
warning light goes out.

5A±37
BRAKE CONTROL SYSTEM
Diagnostic Trouble Codes (DTCs)
When the warning light in the meter remains ON, the
EHCU stores the fault identification and disables the
ABS.
How to display and erase DTCs:
NOTE:

DTCs can be displayed also by TECH 2. Use
ªDiagnostic Trouble Codesº mode.1. How to start DTC display:

Confirm that the vehicle has come to a complete
stop (with the wheels standing still) and that the
brake pedal is not depressed. (Unless these two
condition are satisfied, DTC display cannot be
started.)

With IGN OFF, connect #12 terminal with #4
terminal or # 5 terminal (GND) . Then turn IGN ON.
The DLC is located behind the driver side kick panel
350R200001

Keep #12 terminal connected with #4 terminal or # 5
terminal (GND) during DTC display. (If #12 terminal
is separated from #4 terminal or # 5 terminal (GND)
during display, display will stop.)
2. DTC display:

DTC is displayed by blinking warning light.

Double-digit display.

First, normal DTC 12 is displayed three times and
then any other DTCs are displayed three times. (If
no other DTCs have been stored, the display of DTC
12 will be repeated.)3. How to erase code:

Conduct brake switch ON/OFF operation 6 or more
times within 3 seconds of self-diagnosis startup.

The code cannot be erased if more than 3 seconds
have passed since self-diagnosis startup, or if
self-diagnosis has started with brake switched on
(brake pedaled).
B05RW005

5A±38BRAKE CONTROL SYSTEM
4. Notes

If the following should occur during Diagnostic
Trouble Code (DTC) display, the display will be
discontinued. After initial check, the status that is
under the control of ABS will be returned :
± The vehicle starts (The wheels turn) or the brake
pedal is depressed.

Up to 3 different codes can be stored.

If the ABS should turn OFF due to an intermittent
defect, the system will be restored at the next key
cycle, if the initial check finds no abnormality (when
IGN is switched from OFF to ON).
5. An example of DTC display
B05R100001
After displaying DTC 12 three times, one DTC after
another is displayed, starting with the most recent
one. (However, display is discontinued after about 5
minutes.)
B05R100002
The DTC 12 is displayed repeatedly. (display is
discontinued after about 5 minutes after)

5A±39
BRAKE CONTROL SYSTEM
Chart B-1 With the key in the ON position (Before starting the engine). Warning light (W/L)
is not activated.
StepActionYe sNo
1Is W/L fuse disconnected?Replace fuse.
Go to
Step 5Go to Step 2
2Is W/L burnt out?Replace W/L
bulb.
Go to
Step 5Go to Step 3
31. Turn the key off.
2. Disconnect coil integrated module connector (C-6).
3. Turn the key ON.
Is the check voltage between coil integrated module connector
(C-6) terminals 6 and 7 the battery voltage?
Go to Step 4
Repair harness
and connector.
Go to
Step 5
4Is there the continuity between coil integrated module connector
(C-6) terminals, 1 and 7 and body ground.Check harness
for suspected
disconnection
No fault found:
Replace EHCU.
Go to
Step 5
Repair harness
and connector.
Go to
Step 5
5Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 5
Chart B-2 CPU Error (DTC 14 (Flash out) / C0271, C0272, C0273, C0284 (Serial
communications))
StepActionYe sNo
11. Turn the key off.
2. Disconnected coil integrated module connector.
3. Inspect coil integrated module ground.
Is there the continuity between the coil integrated module
connector terminals, 2 (C-5) and 7 (C-6) and body ground?
Go to Step 2
Repair the body
ground harness.
Go to
Step 3
21. Turn the key off, connect the coil integrated module connector.
2. Erase the trouble code.
3. Turn Ignition off, then on, to perform system self-check.
4. If warning light remains on, display trouble codes once again.
Is the trouble code the DTC 14 (Flash out) / C0271, C0272,
C0273, C0284 (Serial communications)?
Replace EHCU.
Go to
Step 3
Inspect in
accordance with
the DTC
displayed.
31. Reconnect all components, ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat the ªBasic
diagnostic flow
chartº
Go to Step 3

5A±52BRAKE CONTROL SYSTEM
Chart B-24 Wheel Speed Input Abnormality (DTC 65 (Flash out) / C0238 (Serial
communications))
StepActionYe sNo
1Using TECH 2?Go to Step 2Go to Step 3
21. Connect TECH 2.
2. Select Snap shot manual trigger.
3. With wheel speed data displayed, run the vehicle when speed
has arrived at 30 km/h (18 mph).
4. Check speed data on each wheel (refer to the criterion given
below). * 1
Is the abnormal sensor condition found?
Replace.
Go to
Step 8
Go to Step 3
All the sensors
should follow the
following
flowchart (without
using TECH 2).
3Is there play in sensor/sensor ring?Repair.
Go to
Step 8Go to Step 4
4Is there powdered iron sticking to sensor/sensor ring?Repair.
Go to
Step 8Go to Step 5
5Is there a broken tooth or indentation in sensor ring?Replace sensor
ring.
Go to
Step 8Go to Step 6
6Is there play in wheel bearing?Adjust or repair.
Go to
Step 8Go to Step 7
7Is the check wiring between sensor and coil integrated module
normal?
Replace EHCU.
Go to
Step 8
Repair, and
perform system
self-check.
Go to
Step 8
81. Reconnect all components, ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat `Basic
diagnostic flow
chartº
Go to Step 8
Sensor Signal Abnormality Criteria using TECH 2
1. While driving, the speed of one or two wheels is 25%
or more higher or lower than that of the other wheels.
2. The speed of one or two wheels is 10 km/h (6 mph) or
more higher or lower than that of the other wheels.
3. During steady driving, wheel speed changes abruptly.
*1 The vehicle must run on a level paved road.
NOTE: Even after repairing the faulty part the warning
light (W/L) does not go out if the vehicle is at a stop.
Turn the ignition switch to the ON position and drive the
vehicle at 12 km/h (8 mph) or higher to make sure that the
warning light goes out.
It is important to verify that the correct tires are installed
on vehicle.

6E±35
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Inspect all wires in the engine compartment for proper
connections, burned or chafed spots, pinched wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing diagnostic procedures could result in an
incorrect diagnosis or damage to powertrain
components. Do not attempt to diagnose a powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class 2 Serial Data Communications
Government regulations require that all vehicle
manufacturers establish a common communication
system. This vehicle utilizes the ªClass 2º communication
system. Each bit of information can have one of two
lengths: long or short. This allows vehicle wiring to be
reduced by transmitting and receiving multiple signals
over a single wire. The messages carried on Class 2 data
streams are also prioritized. If two messages attempt to
establish communications on the data line at the same
time, only the message with higher priority will continue.
The device with the lower priority message must wait.
The most significant result of this regulation is that it
provides Scan tool manufacturers with the capability to
access data from any make or model vehicle that is sold.
The data displayed on other Scan tools will appear the
same, with some exceptions. Some Scan tools will only
be able to display certain vehicle parameters as values
that are a coded representation of the true or actual value.
On this vehicle the Scan tool displays the actual values for
vehicle parameters. It will not be necessary to perform
any conversions from coded values to actual values.
On-Board Diagnostic (OBD II)
On-Board Diagnostic Tests
A diagnostic test is a series of steps, the result of which is
a pass or fail reported to the diagnostic executive. When
a diagnostic test reports a pass result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The diagnostic test has passed during the current
ignition cycle.

The fault identified by the diagnostic test is not
currently active.
When a diagnostic test reports a fail result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The fault identified by the diagnostic test is currently
active.

The fault has been active during this ignition cycle.

The operating conditions at the time of the failure.Remember, a fuel trim DTC may be triggered by a list of
vehicle faults. Make use of all information available (other
DTCs stored, rich or lean condition, etc.) when
diagnosing a fuel trim fault.
Comprehensive Component Monitor
Diagnostic Operation
Comprehensive component monitoring diagnostics are
required to monitor emissions-related input and output
powertrain components. The
CARB OBD II
Comprehensive Component Monitoring List Of
Components Intended To illuminate MIL
is a list of
components, features or functions that could fall under
this requirement.
Input Components:
Input components are monitored for circuit continuity and
out-of-range values. This includes rationality checking.
Rationality checking refers to indicating a fault when the
signal from a sensor does not seem reasonable, i.e.
Throttle Position (TP) sensor that indicates high throttle
position at low engine loads or MAP voltage. Input
components may include, but are not limited to the
following sensors:

Vehicle Speed Sensor (VSS)

Crankshaft Position (CKP) sensor

Throttle Position (TP) sensor

Engine Coolant Temperature (ECT) sensor

Manifold Absolute Pressure (MAP) sensor

Mass Air Flow (MAF) sensor
In addition to the circuit continuity and rationality check,
the ECT sensor is monitored for its ability to achieve a
steady state temperature to enable closed loop fuel
control.
Output Components:
Output components are diagnosed for proper response to
control module commands. Components where
functional monitoring is not feasible will be monitored for
circuit continuity and out-of-range values if applicable.
Output components to be monitored include, but are not
limited to, the following circuits:

Control module controlled EVAP Canister Purge
Valve

Electronic Transmission controls

A/C relays

VSS output

MIL control

Cruise control inhibit
Refer to PCM and Sensors in General Descriptions.
Passive and Active Diagnostic Tests
A passive test is a diagnostic test which simply monitors a
vehicle system or component. Conversely, an active test,
actually takes some sort of action when performing
diagnostic functions, often in response to a failed passive
test. For example, the EGR diagnostic active test will
force the EGR valve open during closed throttle decel
and/or force the EGR valve closed during a steady state.
Either action should result in a change in manifold
pressure.

6E±36
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Intrusive Diagnostic Tests
This is any on-board test run by the Diagnostic
Management System which may have an effect on
vehicle performance or emission levels.
Warm-Up Cycle
A warm-up cycle means that engine at temperature must
reach a minimum of 70
C (160
F)
and rise at least 22
C
(40
F) over the course of a trip.
Freeze Frame
Freeze Frame is an element of the Diagnostic
Management System which stores various vehicle
information at the moment an emissions-related fault is
stored in memory and when the MIL is commanded on.
These data can help to identify the cause of a fault. Refer
to
Storing And Erasing Freeze Frame Data in this section
for more detailed information.
Failure Records
Failure Records data is an enhancement of the OBD II
Freeze Frame feature. Failure Records store the same
vehicle information as does Freeze Frame, but it will store
that information for any fault which is stored in on-board
memory, while Freeze Frame stores information only for
emission-related faults that command the MIL on.
System Status and Drive Cycle for
Satisfying Federal Inspection/Maintenance
(I/M 240) Regulations
I/M Ready Status means a signal or flag for each
emission system test that had been set in the PCM. I/M
Ready Status indicates that the vehicle on-board
emissions diagnostics have been run. I/M Ready Status
is not concerned whether the emission system passed or
failed the test, only that on-board diagnosis is complete.
Not all vehicles use all possible I/M flags.
Common OBD II Terms
Diagnostic
When used as a noun, the word diagnostic refers to any
on-board test run by the vehicle's Diagnostic
Management System. A diagnostic is simply a test run on
a system or component to determine if the system or
component is operating according to specification. There
are many diagnostics, shown in the following list:

Misfire

Oxygen sensors

Oxygen sensor heaters

EGR

Catalyst monitoring
Enable Criteria
The term ªenable criteriaº is engineering language for the
conditions necessary for a given diagnostic test to run.
Each diagnostic has a specific list of conditions which
must be met before the diagnostic will run. ªEnable
criteriaº is another way of saying ªconditions requiredº.The enable criteria for each diagnostic is listed on the first
page of the DTC description in Section 6E under the
heading ªConditions for Setting the DTCº. Enable criteria
varies with each diagnostic, and typically includes, but is
not limited to the following items:

engine speed

vehicle speed

ECT

MAF/MAP

barometric pressure

IAT

TP

high canister purge

fuel trim

TCC enabled

A/C on
Trip
Technically, a trip is a key on-run-key off cycle in which all
the enable criteria for a given diagnostic are met, allowing
the diagnostic to run. Unfortunately, this concept is not
quite that simple. A trip is official when all the enable
criteria for a given diagnostic are met. But because the
enable criteria vary from one diagnostic to another, the
definition of trip varies as well. Some diagnostics are run
when the vehicle is at operating temperature, some when
the vehicle first starts up; some require that the vehicle be
cruising at a steady highway speed, some run only when
the vehicle is idle; some diagnostics function with the
TCC disabled. Some run only immediately following a
cold engine start-up.
A trip then, is defined as a key on-run-key off cycle in
which the vehicle was operated in such a way as to satisfy
the enabling criteria for a given diagnostic, and this
diagnostic will consider this cycle to be one trip. However,
another diagnostic with a different set of enable criteria
(which were not met) during this driving event, would not
consider it a trip. No trip will occur for that particular
diagnostic until the vehicle is driven in such a way as to
meet all the enable criteria.
The Diagnostic Executive
The Diagnostic Executive is a unique segment of
software which is designed to coordinate and prioritize
the diagnostic procedures as well as define the protocol
for recording and displaying their results. The main
responsibilities of the Diagnostic Executive are listed as
the following:

Commanding the MIL (ªCheck Engineº lamp) on and
off

DTC logging and clearing

Freeze Frame data for the first emission related DTC
recorded

Non-emission related Service Lamp

Operating conditions Failure Records buffer, (the
number of records will vary)

Current status information on each diagnostic

System Status (I/M ready)

6E±39
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Identifying stored Diagnostic Trouble Codes (DTCs).

Clearing DTCs.

Performing output control tests.

Reading serial data.
TS24064
Decimal/Binary/Hexadecimal Conversions
Beginning in 1996, Federal Regulations require that all
auto manufacturers selling vehicles in the United States
provide Scan Tool manufacturers with software
information to display vehicle operating parameters. All
Scan Tool manufacturers will display a variety of vehicle
information which will aid in repairing the vehicle. Some
Scan Tools will display encoded messages which will aid
in determining the nature of the concern. The method of
encoding involves the use of a two additional numbering
systems: Binary and Hexadecimal.
The binary number system has a base of two numbers.
Each digit is either a 0 or a 1. A binary number is an eight
digit number and is read from right to left. Each digit has a
position number with the farthest right being the 0 position
and the farthest left being the 7 position. The 0 position,
when displayed by a 1, indicates 1 in decimal. Each
position to the left is double the previous position and
added to any other position values marked as a 1.
A hexadecimal system is composed of 16 different alpha
numeric characters. The alpha numeric characters used
are numbers 0 through 9 and letters A through F. The
hexadecimal system is the most natural and common
approach for Scan Tool manufacturers to display data
represented by binary numbers and digital code.
Verifying Vehicle Repair
Verification of vehicle repair will be more comprehensive
for vehicles with OBD II system diagnostic. Following a
repair, the technician should perform the following steps:
1. Review and record the Fail Records and/or Freeze
Frame data for the DTC which has been diagnosed
(Freeze Frame data will only be stored for an A or B
type diagnostic and only if the MIL has been
requested).
2. Clear DTC(s).
3. Operate the vehicle within conditions noted in the Fail
Records and/or Freeze Frame data.
4. Monitor the DTC status information for the DTC which
has been diagnosed until the diagnostic test
associated with that DTC runs.
Following these steps are very important in verifying
repairs on OBD ll systems. Failure to follow these steps
could result in unnecessary repairs.
Reading Diagnostic Trouble Codes Using
The Tech 2 Scan Tool
The procedure for reading diagnostic trouble code(s) is to
use a diagnostic Scan Tool. When reading DTC(s), follow
instructions supplied by tool manufacturer.
Clearing Diagnostic Trouble Codes
IMPORTANT:Do not clear DTCs unless directed to do
so by the service information provided for each diagnostic
procedure. When DTCs are cleared, the Freeze Frame
and Failure Record data which may help diagnose an
intermittent fault will also be erased from memory.
If the fault that caused the DTC to be stored into memory
has been corrected, the Diagnostic Executive will begin to
count the ªwarm-upº cycles with no further faults
detected, the DTC will automatically be cleared from the
PCM memory.
To clear Diagnostic Trouble Codes (DTCs), use the
diagnostic Scan Tool ªclear DTCsº or ªclear informationº
function. When clearing DTCs follow instructions
supplied by the tool manufacturer.
When a Scan Tool is not available, DTCs can also be
cleared by disconnecting
one of the following sources for
at least thirty (30) seconds.
NOTE: To prevent system damage, the ignition key must
be ªOFFº when disconnecting or reconnecting battery
power.

The power source to the control module. Examples:
fuse, pigtail at battery PCM connectors, etc.

The negative battery cable. (Disconnecting the
negative battery cable will result in the loss of other
on-board memory data, such as preset radio tuning).

6E±41
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Tech 2 Features
1. Tech 2 is a 12 volt system. Do not apply 24 volts.
2. After connecting and/or installing the Vehicle
Communications Interface (VCI) module, PCMCIA
card and DLC connector to the Tech 2, connect the
tool to the vehicle DLC.
3. Make sure the Tech 2 is OFF when removing or
installing the PCMCIA card.
4. The PCMCIA card has a capacity of 10 Megabytes
which is 10 times greater than the memory of the Tech
1 Mass Storage Cartridge.
5. The Tech 2 has the capability of two snapshots.
6. The PCMCIA card is sensitive to magnetism and
static electricity, so care should be taken in the
handling of the card.
7. The Tech 2 can plot a graph when replaying a
snapshot.
8. Always return to the Main Menu by pressing the EXIT
key several times before shutting down.
9. To clear Diagnostic Trouble Codes (DTCs), open
Application Menu and press ªF1: Clear DTC Infoº.
Getting Started

Before operating the Isuzu PCMCIA card with the
Tech 2, the following steps must be performed:
1. Insert the Isuzu system PCMCIA card (1) into the
Tech 2 (5).
2. Connect the SAE 16/19 adapter (3) to the DLC cable
(4).
3. Connect the DLC cable to the Tech 2 (5)
4. Make sure the vehicle ignition is off.
5. Connect the Tech 2 SAE 16/19 adapter to the vehicle
DLC.
826RW002
6. Turn on the vehicle ignition.7. Power the Tech 2 ON and verify the Tech 2 power up
display.
060RW009
NOTE: The RS232 Loop back connector is only to use for
diagnosis of Tech 2. Refer to user guide of the Tech 2.

6E±42
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Operating Procedure (For Example)
The power up screen is displayed when you power up the
tester with the Isuzu systems PCMCIA card. Follow the
operating procedure below.
060R100102
060R200038