key ISUZU AXIOM 2002 Service Owner's Manual
Page 669 of 2100
5A±50BRAKE CONTROL SYSTEM
Chart B-22 Rear Speed Sensor Missing Signal (DTC 63 (Flash out) / C0236, C0237 (Serial
communications))
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Measure the Rear speed sensor resistance between coil
integrated module connector (C-6) terminals 4 and 12.
Is the resistance between 1.0k and 1.7k ohms?
Go to Step 2Go to Step 3
2Is there play sensor/sensor rotor?Repair.
Go to
Step 6Go to Step 4
3Measure the rear speed sensor resistance at the sensor
connector.
Is the resistance between 1.0k and 1.7k ohms?Repair harness
abnormality
between sensors
and coil
integrated
module.
Go to
Step 6
Replace sensor.
Go to
Step 6
4Damage and powered iron sticking to sensor/sensor ring?Repair.
Go to
Step 6Go to Step 5
5Is sensor output normal? (Chart C-1-3 or TC-1)Check for faults
in harness
between speed
sensor and coil
integrated
module.
Fault found:
repair, and
perform system
self-check.
No fault found:
replace EHCU.
Go to
Step 6
Replace sensor.
Go to
Step 6
61. 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 6
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.
Page 670 of 2100
5A±51
BRAKE CONTROL SYSTEM
Chart B-23 Simultaneous Drop-out of Front Speed Sensor Signal (DTC 64 (Flash out) /
C0229 (Serial communications))
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Measure the FL speed sensor resistance between coil
integrated module connector (C-6) terminals 2 and 10.
Is the resistance between 2.0k and 2.8k ohms?
Go to Step 2Go to Step 3
2Measure the FR speed sensor resistance between coil integrated
module connector (C-6) terminals 3 and 11.
Is the resistance between 2.0k and 2.8 k ohms?
Go to Step 5Go to Step 4
3Measure the FL speed sensor resistance at the sensor connector.
Is the resistance between 2.0k and 2.8k ohms?Repair harness
abnormality
between sensors
and coil
integrated
module.
Go to
Step 2
Replace sensor.
Go to
Step 2
4Measure the FR speed sensor resistance at the sensor
connector.
Is the resistance between 2.0k and 2.8k ohms?Repair harness
abnormality
between sensors
and coil
integrated
module.
Go to
Step 5
Replace sensor.
Go to
Step 5
5Damage and powered iron sticking to sensor/sensor ring?Repair.
Go to
Step 6Go to Step 6
6Is there play sensor/sensor rotor?Repair.
Go to
Step 7Go to Step 7
7Is sensor output normal? (Chart C-1-1&C-1-2 or TC-1)Check for faults
in harness
between speed
sensor and coil
integrated
module.
Fault found:
repair, and
perform system
self-check.
No fault found:
replace EHCU.
Go to
Step 8
Replace sensor.
Go to
Step 8
81. Reconnect all components, ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat ªBasic
diagnostic flow
chartº
Go to Step 8
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.
Page 672 of 2100
5A±53
BRAKE CONTROL SYSTEM
Unit Inspection Procedure
This section describes the following inspection
procedures referred to during
Symptom Diagnosis and
Diagnosis By ªABSº Warning Light Illumination Pattern
without TECH 2with TECH 2
Sensor Output InspectionChart C-1-1 to C-1-3Chart TC-1
Chart C-1-1 FL Sensor Output Inspection Procedure
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Jack up the vehicle with all four wheels off the ground.
Measure the AC voltage between coil integrated module
connector terminals while turning FL wheel at a speed of 1
RPS:
Is the voltage between coil integrated module connector (C-6)
terminals 2 and 10 less than 200 mV?
Go to Step 2
OK.
Go to
Step 3
21. Disconnect the wheel speed sensor.
2. Measure resistance between the wheel speed sensor
connector terminals 1 and 2.
Is the check between connector (C-28) terminals 1 and 2 within
2.0k - 2.8k ohms?Connector is
faulty, or open or
short circuit of
harness between
wheel speed
sensor connector
and coil
integrated
module.
Inspect and
correct the
connector or
harness.
Go to
Step 3
Wheel speed
sensor is faulty.
Replace the
wheel speed
sensor.
Go to
Step 3
3Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 3
Page 673 of 2100
5A±54BRAKE CONTROL SYSTEM
Chart C-1-2 FR Sensor Output Inspection Procedure
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Jack up the vehicle with all four wheels off the ground.
Measure the AC voltage between coil integrated module
connector terminals while turning FR wheel at a speed of 1
RPS:
Is the voltage between coil integrated module connector (C-6)
terminals 3 and 11 less than 200 mV?
Go to Step 2
OK.
Go to
Step 3
21. Disconnect the wheel speed sensor.
2. Measure resistance between the wheel speed sensor
connector terminals 1 and 2.
Is the check between connector (C-1) terminals 1 and 2 within
2.0k - 2.8k ohms?Connector is
faulty, or open or
short circuit of
harness between
wheel speed
sensor connector
and coil
integrated
module.
Inspect and
correct the
connector or
harness.
Go to
Step 3
Wheel speed
sensor is faulty.
Replace the
wheel speed
sensor.
Go to
Step 3
3Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 3
Chart C-1-3 Rear Sensor Output Inspection Procedure
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Jack up the vehicle with all four wheels off the ground measure
the AC voltage between coil integrated module connector
terminals while turning Rear wheel at a speed of 1 RPS:
Is the check between coil integrated module connector (C-6)
terminals 4 and 12 than under 200 mV?
Go to Step 2
OK.
Go to
Step 3
21. Disconnect the wheel speed sensor.
2. Measure resistance between the wheel speed sensor
connector terminals 1 and 2.
Is the check between connector (F-4) terminals 1 and 2 within
1.0k - 1.7k ohms?Connector is
faulty, or open or
short circuit of
harness between
wheel speed
sensor connector
and coil
integrated
module.
Inspect and
correct the
connector or
harness.
Go to
Step 3
Wheel speed
sensor is faulty.
Replace the
wheel speed
sensor.
Go to
Step 3
3Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 3
Page 926 of 2100
6C±9 ENGINE FUEL (6VE1 3.5L)
NOTE: Do not use tools of any kind. Only use bare hands
when disconnecting the connector. Use a lubricant (light
oil) and/or push and pull the connector until the pipe is
disconnected.
Cover the connectors that was removed with a plastic
bag, to prevent dust or rain water from entering.
140R100028
Reuse of Quick±Connector
Replace the port and connector if scratch, dent or
crack is found.
Remove any dirt build up on the port when installing
the connector. Replace the connector, if there is any
forms of rust, dent, scratch.
After cleaning the port, insert it straight into the
connector until it clicks. After it clicks, try pulling it out
to make sure that it is not drawn and is securely
locked.
140R100036
Assembling Advice
By applying engine oil or light oil to the pipe, port makes
pipe assembly easier. The pipe assembly should take
place immediately after applying oil (to prevent dust from
sticking to the pipe surface ± which may decrease sealing
ability).
Test/Inspection After Assembling
1. Reconnect the battery negative cable.
2. Turn the ignition key to the ªONº position and listen for
pump start-up sound. Inspect for leaks, the fuel
pressure will increase as the fuel pump is actuated.
3. Perform leak inspection (step 2) several times.
4. Start the engine and observe the engine idle speed.
The presence of dirt in the fuel system may affect the
fuel injection system.
Page 927 of 2100
6C±10
ENGINE FUEL (6VE1 3.5L)
Fuel Pump Relay
General Description
In order to control the fuel pump and sender (FPS)
operation, the FPS relay is provided. When the starter
switch is turned to ªONº position, the FPS relay operates
the FPS for 2 seconds.
When the key is turned to ªSTARTº position, the Engine
Control Module receives the reference pulse from the
Ignition Control Module and it operates the relay, again
causing the FPS to feed fuel.
Fuel Tank
Fuel Tank and Associated Parts
140R200006
Legend
(1) Fuel Tank Assembly
(2) Fuel Tank Fixing Bolt (QTY: 5)
(3) Fuel Tank Fixing Nut (QTY: 1)
(4) Separator Fixing Bolt (QTY: 2)
(5) Fuel Filler Hose(6) Fuel Vent Hose
(7) Fuel Feed Hose
(8) Fuel Return Hose
(9) Vapor Pressure Sensor Connector
(10) Fuel Feed Pump Connector
Page 1001 of 2100
6E±34
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
dissatisfaction. The following list of non-vehicle faults
does not include every possible fault and may not apply
equally to all product lines.
Fuel Quality
Fuel quality is not a new issue for the automotive industry,
but its potential for turning on the MIL (ªCheck Engineº
lamp) with OBD II systems is new.
Fuel additives such as ªdry gasº and ªoctane enhancersº
may affect the performance of the fuel. If this results in an
incomplete combustion or a partial burn, it will show up as
a Misfire DTC P0300. The Reed Vapor Pressure of the
fuel can also create problems in the fuel system,
especially during the spring and fall months when severe
ambient temperature swings occur. A high Reed Vapor
Pressure could show up as a Fuel Trim DTC due to
excessive canister loading. High vapor pressures
generated in the fuel tank can also affect the Evaporative
Emission diagnostic as well.
Using fuel with the wrong octane rating for the vehicle
may cause driveability problems. Many of the major fuel
companies advertise that using ªpremiumº gasoline will
improve the performance of the vehicle. Most premium
fuels use alcohol to increase the octane rating of the fuel.
Although alcohol-enhanced fuels may raise the octane
rating, the fuel's ability to turn into vapor in cold
temperatures deteriorates. This may affect the starting
ability and cold driveability of the engine.
Low fuel levels can lead to fuel starvation, lean engine
operation, and eventually engine misfire.
Non-OEM Parts
All of the OBD II diagnostics have been calibrated to run
with OEM parts. Something as simple as a
high-performance exhaust system that affects exhaust
system back pressure could potentially interfere with the
operation of the EGR valve and thereby turn on the MIL
(ªCheck Engineº lamp). Small leaks in the exhaust
system near the post catalyst oxygen sensor can also
cause the MIL (ªCheck Engineº lamp) to turn on.
Aftermarket electronics, such as transceivers, stereos,
and anti-theft devices, may radiate EMI into the control
system if they are improperly installed. This may cause a
false sensor reading and turn on the MIL (ªCheck Engineº
lamp).
Environment
Temporary environmental conditions, such as localized
flooding, will have an effect on the vehicle ignition system.
If the ignition system is rain-soaked, it can temporarily
cause engine misfire and turn on the MIL (ªCheck Engineº
lamp).
Refueling
A new OBD II diagnostic was introduced in 1996 on some
vehicles. This diagnostic checks the integrity of the entire
evaporative emission system. If the vehicle is restarted
after refueling and the fuel cap is not secured correctly,
the on-board diagnostic system will sense this as a
system fault and turn on the MIL (ªCheck Engineº lamp)
with a DTC P0440.Vehicle Marshaling
The transportation of new vehicles from the assembly
plant to the dealership can involve as many as 60 key
cycles within 2 to 3 miles of driving. This type of operation
contributes to the fuel fouling of the spark plugs and will
turn on the MIL (ªCheck Engineº lamp) with a P0300
Misfire DTC.
Poor Vehicle Maintenance
The sensitivity of OBD II diagnostics will cause the MIL
(ªCheck Engineº lamp) to turn on if the vehicle is not
maintained properly. Restricted air filters, fuel filters, and
crankcase deposits due to lack of oil changes or improper
oil viscosity can trigger actual vehicle faults that were not
previously monitored prior to OBD II. Poor vehicle
maintenance can't be classified as a ªnon-vehicle faultº,
but with the sensitivity of OBD II diagnostics, vehicle
maintenance schedules must be more closely followed.
Related System Faults
Many of the OBD II system diagnostics will not run if the
PCM detects a fault on a related system or component.
One example would be that if the PCM detected a Misfire
fault, the diagnostics on the catalytic converter would be
suspended until Misfire fault was repaired. If the Misfire
fault was severe enough, the catalytic converter could be
damaged due to overheating and would never set a
Catalyst DTC until the Misfire fault was repaired and the
Catalyst diagnostic was allowed to run to completion. If
this happens, the customer may have to make two trips to
the dealership in order to repair the vehicle.
Emissions Control Information Label
The engine compartment ªVehicle Emissions Control
Information Labelº contains important emission
specifications and setting procedures. In the upper left
corner is exhaust emission information. This identifies
the emission standard (Federal, California, or Canada) of
the engine, the displacement of the engine in liters, the
class of the vehicle, and the type of fuel metering system.
There is also an illustrated emission components and
vacuum hose schematic.
This label is located in the engine compartment of every
vehicle. If the label has been removed it should be
replaced. It can be ordered from Isuzu Dealership.
Visual / Physical Engine Compartment
Inspection
Perform a careful visual and physical engine
compartment inspection when performing any diagnostic
procedure or diagnosing the cause of an emission test
failure. This can often lead to repairing a problem without
further steps. Use the following guidelines when
performing a visual/physical inspection:
Inspect all vacuum hoses for pinches, cuts,
disconnections, and proper routing.
Inspect hoses that are difficult to see behind other
components.
Page 1003 of 2100
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 70C (160F)
and rise at least 22C
(40F) 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)
Page 1004 of 2100
6E±37
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
The Diagnostic Executive records DTCs and turns on the
MIL when emission-related faults occur. It can also turn
off the MIL if the conditions cease which caused the DTC
to set.
Diagnostic Information
The diagnostic charts and functional checks are designed
to locate a faulty circuit or component through a process
of logical decisions. The charts are prepared with the
requirement that the vehicle functioned correctly at the
time of assembly and that there are no multiple faults
present.
There is a continuous self-diagnosis on certain control
functions. This diagnostic capability is complemented by
the diagnostic procedures contained in this manual. The
language of communicating the source of the malfunction
is a system of diagnostic trouble codes. When a
malfunction is detected by the control module, a
diagnostic trouble code is set and the Malfunction
Indicator Lamp (MIL) (ªCheck Engineº lamp) is
illuminated.
Malfunction Indicator Lamp (MIL)
The Malfunction Indicator Lamp (MIL) looks the same as
the MIL you are already familiar with (ªCheck Engineº
lamp). However, OBD II requires that it illuminate under a
strict set of guide lines.
Basically, the MIL is turned on when the PCM detects a
DTC that will impact vehicle emissions.
The MIL is under the control of the Diagnostic Executive.
The MIL will be turned on if an emissions-related
diagnostic test indicates a malfunction has occurred. It
will stay on until the system or component passes the
same test, for three consecutive trips, with no emissions
related faults.
If the vehicle is experiencing a misfire malfunction which
may cause damage to the Three-Way Catalytic
Converter (TWC), the MIL will flash once per second.
This will continue until the vehicle is outside of speed and
load conditions which could cause possible catalyst
damage, and the MIL will stop flashing and remain on
steady.
Extinguishing the MIL
When the MIL is on, the Diagnostic Executive will turn off
the MIL after
three(3) consecutive trips that a ªtest
passedº has been reported for the diagnostic test that
originally caused the MIL to illuminate.
Although the MIL has been turned off, the DTC will remain
in the PCM memory (both Freeze Frame and Failure
Records) until
forty(40) warm-up cycles after no faults
have been completed.
If the MIL was set by either a fuel trim or misfire-related
DTC, additional requirements must be met. In addition to
the requirements stated in the previous paragraph, these
requirements are as follows:
The diagnostic tests that are passed must occur
within 375 RPM of the RPM data stored at the time the
last test failed.
Plus or minus ten (10) percent of the engine load that
was stored at the time the last failed.Similar engine temperature conditions (warmed up or
warming up ) as those stored at the time the last test
failed.
Meeting these requirements ensures that the fault which
turned on the MIL has been corrected.
The MIL (ªCheck Engineº lamp) is on the instrument
panel and has the following function:
It informs the driver that a fault affects vehicle
emission levels has occurred and that the vehicle
should be taken for service as soon as possible.
As a bulb and system check, the MIL will come ªONº
with the key ªONº and the engine not running. When
the engine is started, the MIL will turn ªOFF.º
When the MIL remains ªONº while the engine is
running, or when a malfunction is suspected due to a
driveability or emissions problem, a Powertrain
On-Board Diagnostic (OBD ll) System Check must be
performed. The procedures for these checks are
given in On-Board Diagnostic (OBD) System Check.
These checks will expose faults which may not be
detected if other diagnostics are performed first.
DTC Types
Each DTC is directly related to a diagnostic test. The
Diagnostic Management System sets DTC based on the
failure of the tests during a trip or trips. Certain tests must
fail two (2) consecutive trips before the DTC is set. The
following are the four (4) types of DTCs and the
characteristics of those codes:
Type A
Emissions related
Requests illumination of the MIL of the first trip with a
fail
Stores a History DTC on the first trip with a fail
Stores a Freeze Frame (if empty)
Stores a Fail Record
Updates the Fail Record each time the diagnostic
test fails
Type B
Emissions related
ªArmedº after one (1) trip with a fail
ªDisarmedº after one (1) trip with a pass
Requests illumination of the MIL on the
second
consecutive trip
with a fail
Stores a History DTC on the second consecutive trip
with a fail (The DTC will be armed after the first fail)
Stores a Freeze Frame on the second consecutive
trip with a fail (if empty)
Stores a Fail Record when the first test fails (not
dependent on
consecutive trip fails)
Updates the Fail Record each time the diagnostic
test fails
(Some special conditions apply to misfire and fuel trim
DTCs)
Type C (if the vehicle is so equipped)
Non-Emissions related
Requests illumination of the Service
Stores a History DTC on the
first trip with a fail
Page 1006 of 2100
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).