scan tool basics obd2

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Scan Tool Basics
This will help you prepare for the NC3 – Snap‐on Scan Tool Certification .
Front‐Door vs Back‐Door Diagnostics
To diagnose a computer control system you can go to the “Front Door” or the
“Back Door”. The Front Door is where sensor data (input) enters and actuator
data (output) leaves the computer. You go in the Back Door by using a scan tool
to find what the computer is thinking.
Diagnosis often starts at the Back Door. The back door is found at the data link
connector (DLC) where you connect the scan tool to the vehicle. On a modern
vehicle you can use a scan tool to access the Back Door for multiple vehicle
control modules such as the engine, transmission, instrument cluster, tire
pressure monitor, ABS system, power windows, etc. Back Door Checks include:
Diagnostic Trouble Codes (DTC’s), Input and Output Data (called Parameter
Identifiers or PID’s), Graphing PID Data (used to view the relationships between
different PID’s), and using the diagnostic Troubleshooter. The Troubleshooter
software found in the scan tool will list procedures to test that component or
system.
The scan tool (back door) will help you decide which Front Door tests are needed
to solve the problem. Front Door tests can be made on input signals (from
sensors to the computer), or output command signals used to control the various
actuators (like fuel injection, ignition timing, etc.) just remember, The Front Door
is what is actually happening outside of the computer and the Back Door is what
the computer “thinks” is happening.
Scan tool data (input – output data) and Diagnostic Trouble Codes (DTC’s) are all
found at the back door. Once you know which system to check, you diagnose that
system using Front Door diagnostic tests.

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The scan tool is a BACK‐DOOR directional tool. It never tells you the cause of a
problem, only what’s being affected and where to look. The cause for the
malfunction will almost always be found through the FRONT DOOR.
Who needs to use a scan tool?
It the past only driveability or engine performance technicians needed to use a
scan tool. On modern vehicles you will often use a scan tool to bleed the brakes,
perform and alignment, repair a power window, change the tires, or even change
the oil.
How do I connect the scan tool?
Here is a picture showing the controls of the Solus Pro which is the primary
scan tool we will be using in this class.
Power ON the scan tool, then identify the vehicle you are working on
using the Thumb Pad and the Y or N buttons. It is easy to use these scan tool
control buttons once you have tried it a few times.

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Here is what you see when you first turn on the Solus Pro
As you progress through the menu, it will instruct you to use a specific key such as
the K‐20 key or the S44 key. Below is a picture of what those keys look like.
These plug in to the long black communication cable for the Solus Pro.
The next step is to find the Data Link Connector (DLC) inside your vehicle.
The DLC is a 16‐pin connector found on OBDII equipped vehicles. OBD‐II
standards specify the DLC be located under the dash near the steering column.
If you can’t find it, the Solus Pro will tell you where the DLC is.

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Once you have identified the vehicle on the scan tool, used the proper key, and
connected the communication cable to the DLC, you will need to turn the ignition
key to RUN. The Solus Pro can now “talk” to the vehicle control modules.
What can a scan tool do?
Your scan tool can access many vehicle control modules.
The Powertrain Control Modules (PCM) will control your engine and
transmission. Modern vehicles have many more control modules. There will be a
control module for the instrument cluster, another module for the anti‐lock
brakes, one for the air bags and often there is an electronic control module in
each of the doors. Some vehicles have over 30 different control modules.
It is important to access these control modules to perform tasks such as setting
tire pressure monitors, re‐initializing body controls like power windows, bleeding
brakes, diagnosing dash gauges, etc.
Your scan tool will display Diagnostic Trouble Codes (DTC’s).
Diagnostic Trouble Codes are set when the computer decides a system is not
working correctly. The computer will set a code and may illuminate the
Malfunction Indicator Lamp (MIL) to alert the driver. Diagnostic Trouble Codes
only direct you to which system needs diagnosis, they will not tell you what to
replace! For help in diagnosing DTC’s Snap‐on scan tools provide the Fast‐Track
Troubleshooter. This is a large database of diagnostic procedures that can help
you quickly find the root cause of the Diagnostic Trouble Code.
Your scan tool will show all the Parameter Identifiers (PID’s)
PID’s are the name we use to represent all the input (sensor) and output
(actuator) data. Input Data comes from vehicle sensors and Output Data is
commands sent to the vehicle actuators. PID data is the “Back Door” of your
computer system and shows what the control module thinks is happening. For
instance the PCM monitors the Engine Coolant Temperature. The PID for engine
temperature is ECT. When it is cold the PCM decides to add more fuel by keeping
the fuel injectors on longer. The input signal is from the ECT which is a sensor.
To add more fuel an output signal goes to the fuel injectors, which are actuators.

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PID data will be numbers (like 755 RPM or TPS (throttle position) of 93%. Some
scan tools will display only those numbers (Text). With the Solus Pro you can view
PID data three different ways. You can view the data as Text, a PID List, or a
Graph. By graphing PID data you can view the relationship between any sensor
and actuator. It will show how the PID data changes over time.
Here we are viewing the relationship between the TPS (Throttle Position Sensor)
and engine RPM. The RPM should go higher when we open the throttle and
lower as we close the throttle. At the left end of the graph we see the throttle is
held steady about half way open and the RPM is going Up. When the throttle is
allowed to close the RPM goes down. This is all normal operation. Then the TPS
drops to zero, but the RPM goes back up. Opening the throttle is what causes
engine RPM to increase, however the PID data shows the TPS as fully closed. This
relationship of closed throttle while RPM goes UP indicates there is a defect in the
TPS sensor or the wires going to the TPS.

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Your scan tool can run Functional Tests that fall into four categories.
1) Information tests, 2) Toggle tests, 3) Variable Control tests, and 4) Reset tests.
Information tests provide information such as the VIN number and the
Calibration Part Number. This information is useful when checking to see if the
computer has been updated, or when installing a replacement control module.
Toggle tests allow you to ask the control module to turn ON or OFF various
actuators. An example would be to request that the Malfunction Indicator Lamp
be turned ON or OFF. This is an easy way to test the MIL bulb to see if it is blown
out. Another test might be to toggle ON/OFF the fuel injectors one at a time to
see if the engine RPM drops the same amount for each cylinder. Toggle tests are
found under Functional Tests >> Output Controls.
Variable Control tests are also found in Functional Tests >> Output Controls.
A variable test can command an actuator to run through it’s full range of
adjustment. For example the customer is complaining that the fuel gauge will not
go past ½ full. By selecting Functional Tests >> Output Controls >> Variable
Control >> Fuel Gauge Enable (%) you can command the fuel gauge to display
from 0% (empty) to 50% (1/2 full) to 100% (full). If the gauge now reads full, the
problem is most likely in the fuel sending unit. If the variable control test cannot
get the gauge to read past ½ full, the dash gauge must be defective.
Reset tests are necessary when installing certain components. For example
on some engines replacing the crank position sensor (CKP) will require the
computer to “re‐learn” the new CKP sensor signal. This reset test is called CKP
Variation Learn. On these engines, if you replace the sensor without performing
the reset test, the engine may not idle at the correct speed.
When should I use the scan tool?
When you are diagnosing any engine performance issue the scan tool should be
one of the first diagnostic steps. By looking for codes or viewing PID data you find
which direction your diagnostic path should take. When diagnosing it is a good
idea to check for Technical Service Bulletins (TSB’s). SnapOn scan tools will
provide troubleshooter software that uses this TSB information to help with your
diagnosis. While a scan tool will seldom, if ever, isolate the cause of a problem, it
will send you in the right direction and guide you as to what to check next.

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The MIL lamp is ON but there are no codes!
Upon occasion you will have a vehicle with the Malfunction Indicator Lamp
illuminated but your scan tool does not display any code. All this means is that
you have not looked in the proper control room. Powertrain Control Modules on
modern vehicles all have two basic “Control Rooms”. They are the Original
Equipment Manufacturer (OEM) room and the On Board Diagnostic (OBD‐II)
room.
OEM software uses communication standards set by the specific vehicle
manufacturer. There are many different standards used and they change
depending upon model and year. This is why you need the proper Key hooked
into the Modis Pro communication cable!
OBD‐II software uses a communication standard set by the Environmental
Protection Agency. All manufacturers must use the same communication
standard for OBD‐II functions.
The OBD‐II room is in charge of the MIL. It is the OBD‐II control room that will
decide when to turn on or off the Malfunction Indicator Lamp. It also captures
and stores PID data present at the time the MIL was turned ON. This is called
Freeze Frame data and can be very useful in deciding what was happening when
the failure occurred.
An experienced technician will check both the OEM room and the OBD‐II room
when diagnosing the vehicle.

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The only way to learn a scan tool is to practice with it!
The more you use it, the more powerful of a diagnostic tool it will become. As a
beginner you will not know what many of the PID data abbreviations stand for.
Even experienced technicians will not know them all. When you find a PID you do
not understand, go to: Troubleshooter >> Fast Track Data Scan (Normal Values).
Here the Solus Pro will tell you what that PID means and provide normal or typical
data values for that PID. Do not hesitate to explore the many features of the
Troubleshooter.
Which scan tool should I purchase?
The very cheapest scan tools are often called code readers. They will only give
OBD‐II generic codes. There are many Diagnostic Trouble Codes (DTC’s) stored in
the OEM room of the PCM that will not show up on a code reader. Also code
readers will not display PID data which is vital to diagnosing a modern vehicle.
Because all OBD‐II control rooms use a standardized communication protocol
some less expensive scan tools will only talk to the OBDII control room. They will
show DTC’s and PID data available in the OBD control room only. Remember how
the OBDII room turns on the MIL? Just because the MIL lamp is OFF does not
mean there are no codes. The OEM room will store codes and PID data not found
in the OBD room. A professional needs a scan tool that talks to both the OBDII
room and the OEM room found in modern vehicles.
A quality scan tool with all the features you need to diagnose modern vehicles is
not cheap, and they get more sophisticated every year. For this reason I always
caution students to wait on buying a scan tool. You won’t make much money
when you first start, and the shop you work for should have one or more scan
tools to help you with the tasks an entry level‐apprentice technician performs.
It takes time and effort to gain experience and competence. If you work hard and
keep studying you soon will be earning more money to help buy this expensive
tool. Also, by the time you really need to purchase your own scan tool they will
be faster, better, and maybe even cheaper.

20. Automotive Repair Library, Auto Parts, Accessories, Tools & Equipment, Manuals & Books, Car BLOG, Links, Index,
CarleySoftware
. .
Scan Tool Help
Copyright AA1Car.com
A scan tool is a must for automotive diagnostic work today. When your Check Engine Light is on, you have to access the
vehicle's onboard diagnostics with a code reader, scan tool or scanner software to find out what's wrong. A scan tool
allows you to read faul codes and other diagnostic information.
READING TROUBLE CODES
On most 1995 and older pre-OBD2 domestic vehicles, diagnostic trouble codes can be read manually by grounding or
jumping certain terminals on the vehicle's diagnostic connector. This puts the powertrain control module (PCM) into a self-
diagnostic display mode, causing it flash out the code via the Check Engine Light (Malfunction Indicator Lamp or MIL).
You then look up the code number in a reference chart (such as DTC Code Finder) to find out why the light is on.
The problem with reading manual flash codes is that (1) they are no longer used on most 1996 and newer vehicles (one
exception is Nissan), and (2) counting the series of flashes can be confusing. Most flash codes use a combination of long
and short flashes to indicate double digit codes, and if the vehicle has more than one code, it may be tricky to tell when
one code ends and the next one begins. So the preferred method of reading codes on older vehicles is to use a code
reader or scan tool.
On 1996 and newer vehicles with OBD2, there are no manual flash codes. You must have a code reader or scan tool to
read the codes.
CODE READERS
The most basic diagnostic tool
is a code reader. A code
reader can access and display
codes from your vehicle's
computer. The least expensive
models only display a number

21. while the better ones also provide a definition (some are even
bilingual and can display in English, Spanish or French). Code
readers typically sell for under $50.
A code reader can also clear codes to turn off the Check Engine
light. Some code readers can also display the "ready" status of
various OBD II monitors (ready means the monitor has completed its
self-check process). But a code reader is NOT a scan tool because it
only reads and clears codes. It does NOT display any sensor data or
other system operating information. To read sensor and other system
data, you need some type of scan tool or scanner software.
An important point to keep in mind here is that a fault code by itself
does NOT tell you which part needs to be replaced. The code only
tells you that a fault has been detected, not what caused it. The code
serves as a starting point for further diagnosis. Many people don't
understand this and assume an inexpensive code reader is all they
need to "diagnose" and repair their vehicle.
Also, don't assume all code readers display all codes. They all display "generic" or "global" OBD2 codes ("P0" codes). But
some do not display manufacturer "enhanced codes" ("P1" codes), or if they do, the list of codes may be limited to
domestic vehicles (Ford, GM & Chrysler) and not include any enhanced codes for Asian or European vehicles.
Something else to check before you buy is the model years the code reader can access. Most code readers are for 1996
and newer OBD2 vehicles with a standard OBD2 16-pin connector. Most code readers cannot read codes on 1995 and
older cars or trucks because the connectors are different. However, vehicle-specific code readers are available for older
GM, Ford or Chrysler applications. The same is true for BMW, MINI and some other import applications.
Something else to keep in mind about code readers (and scan tools), is that the list of new DTCs and system data grows
with every new model year. Last year's tool may not work on next year's models. Tools get out-of-date VERY quickly, and
have to be updated with new software via plug-in memory chips, cartridges or internet downloads from the tool supplier. If
you are shopping on ebay for a used code reader or scan tool, make sure it will work on your vehicle, or can be updated
to your vehicle.
SCAN TOOLS
For advanced diagnostics on today's vehicles, a full feature scan tool is an absolute
must. Scan tools for do-it-yourselfers can display sensor values and system data, but
DIY scan tools cannot perform various system self-tests such as checking the
operation of the fuel pump, cooling fan(s), idle speed control motor or solenoid, EGR
solenoid, A/C compressor clutch, fuel injectors, EVAP leak test, EVAP purge controls,
etc. This level of diagnostics requires a professional level scan tool (which are
EXPENSIVE!) with bidirectional (two-way) communication capability and the proper
software for accessing and running these type of tests.
Scan tools have different ranges and capabilities. Entry level "generic" scan tools
typically sell for less than $200. They can read and clear codes, display the status of
the various OBD II system monitors, and display basic operating data such as loop
status (Open or Closed), airflow, coolant temperature, oxygen sensor outputs, throttle
position and other sensor readings, and fuel trim values for diagnostic purposes. Most
of these tools are fairly versatile and work on all domestic makes (Ford, GM &
Chrysler), but may require additional software for Asian and/or European applications.
Entry level scan tools that are sold in auto parts stores are usually designed for do-it-
yourselfers, and lack bidirectional communications capability for liability reasons. They
may also display only a limited number of "PIDs" (Performance Information Data such as sensor values, switch status and
other operational data) compared to a professional level scan tool or factory scan tool.

22. DIY Scan Tool Product Information
Click on the following links to view product information from scan tool manufacturers about each of their products:
Actron Uscan for Smart Phones (New product June 2013)
Actron CP9145 Scan Tool
Actron CP9185 Scan Tool
Actron CP9575 Scan Tool
Actron CP9580 Scanner Plus
Actron AutoScanner Plus with Code Connect (YouTube video demo)
Equus_Innova 3040S Scan Tool
Equus_Innova 3040 Scan Tool (YouTube demo video)
Equus_Innova 3050BSRS Scan Tool with Air Bag capability
Equus_Innova 3120-3130 Scan Tools
Equus_Innova 3160 Scan Tool (YouTube video demo)
PROFESSIONAL LEVEL SCAN TOOL FEATURES
The more
advanced
aftermarket
professional grade
scan tools, by
comparison, can
do most of the
same things an
OEM factory scan
tool can do. They
can access and
display all or most
of the PIDs (with
the proper
software), and they
can access and run all or most of the OEM self-tests (again, with the
proper software).
The better tools typically have better displays, too. These include larger LCD screens with color graphics. The tool may
also have multi-channel scope function that allows data to be displayed as a graph or waveform. This makes is easier to
detect certain kinds of problems that may occur too quickly to notice when looking at numerical data. Many scan tools
also have a "flight recorder" capability that allows data to be captured while the vehicle is being driven, for later analysis.
An add-on 5-gas exhaust gas emission analyzer may also be an option.
Another feature that's available in many professional level scan tools is the ability to flash reprogram PCMs. Flashing a
PCM with updated software may be necessary to correct a driveability or emissions issue. Flashing may also be
necessary if the PCM is replaced. The other option is to get a J2534-compliant "pass-thru" tool that serves as an interface
between the vehicle's PCM and a laptop or desktop PC.
NOTE: Some claims can be misleading. A vendor may say their product or software package covers a long list of makes
and models, but it may be only generic OBD II information. They may not even have enhanced codes for the applications
listed. Others may provide all the OBD II codes but no additional codes for ABS, air bags or other systems beyond the
engine and powertrain. Some may have limited diagnostics and not include all the factory tests or procedures. If you are
not sure exactly what is or is not included, ask before you buy.
Another cost associated with buying a professional scan tool is the cost of annual software updates. Updates are
essential for keeping up with changes that occur every year. Update subscriptions can cost up to $800 per year.
If you are looking for info on a particular scan tool, go to the tool supplier's website and browse their product information
and/or training videos:

23. CLick Here to Vew Auto Enginuity scan tool training videos
Click Here to View OTC scan tool training videos
Click Here to View Snap-On Scan tool training videos
OEM OR AFTERMARKET SCAN TOOL?
OEM factory scan tools provide full access to virtually everything, but are very
expensive compared to many aftermarket general purpose scan tools (though some
of the high end aftermarket tools also cost thousands of dollars depending on their
features). An OEM scan tool may cost $5000 up to $12,000 or more!
OEM scan tools include the Tech II for General Motors applications, New
Generation Star (NGS) tester for Ford/Lincoln/Mercury, DRB III for Chrysler, and a
list of others for the Asian and European makes. Some of these are now obsolete,
having been replaced by more advanced PC-based scanner software in
dealerships. Even so, for home diagnostic work, you can often find one of these
older scan tools reasonably prices on ebay.
Factory scan tools generally provide access to all the diagnostic trouble codes (both
"generic OBD II" and "enhanced"), all the on-board self-test procedures, and all of
the other on-board electronics beyond engine performance and emissions such as
the body control module, ABS module, air bag module, suspension module, climate
control module and so on. The OEM scan tool can also be used to "reset" or
"initiate" a module if it has been replaced (which is often necessary before the
module will function correctly)> Often this involves a special "relearn" procedure that
may only be available with the factory scan tool.
The only drawback with OEM scan tools is that most (with some exceptions) are designed to only work on ONE make of
vehicle, not all makes and models. Consequently, they are well suited for new car dealer technicians but not general
repair shop technicians who usually work on all makes and models.
Most technicians can't afford to own a separate scan tool for each and every vehicle they work on, so most opt for a
general purpose scan tool and add software and hardware to expand its capabilities as needed. Some may also buy one
or two OEM scan tools if they do a lot of work on a particular make (GM, for example, or an import). And they may also
have a basic code reader for making quick code checks.
IS THE SCAN TOOL CAN COMPLIANT?
In recent years, the electrical systems on vehicles on late model vehicles have been using a new onboard
communications protocol called CAN or Controller Area Network. CAN started phasing in in the early 2000s, and became
standard on all 2008 and newer cars and light trucks. CAN uses a much higher baud rate to allow faster communication
between modules. Because of this, CAN vehicles require a scan tool that is CAN-compliant for diagnostics. Most older
scan tools cannot be upgraded to read the newer CAN vehicles. So if you are buying a used older scan tool, keep that in
mind.

24. . Innova 3140 CAN-compliant scan tool. . .
SCANNER SOFTWARE
In addition to dedicated scan tools, you can also buy software that transforms a laptop or desktop PC, PDA, tablet or
smart phone into a code reader or scan tool. Some of these offer very basic functions only while others run essentially the
same software as an OEM scan tool.
The simplest and cheapest packages that sell for a couple hundred dollars or less essentially give you the ability to plug a
laptop, PDA, tablet or smart phone into the diagnostic connector on a 1996 or newer vehicle and use it as a code reader
to display and clear generic OBD2 fault codes. The better packages include enhanced codes for specific vehicle
applications, and also may include the ability to display various PIDs such as sensor voltages, switch status and so on.
The best software also includes graphics for displaying sensor voltages and other data.
Scanner software for a laptop, PC, tablet or smart phone requires either an interface cable that plugs into the OBD2
connector, or a WiFi or Bluethooth connection so your vehicle can communicate with your electronic device. The scan
tool software, by itself, is useless without the cable or wireless interface that connects your computer or electronic device
to your vehicle. If you are resourceful and want to save a few bucks, there are numerous sources on the Internet where
you can buy interface cables separately, or kits or plans to build your own USB OBD cable.
One of the advantages of using a laptop or desktop PC as a scan tool is having a large display (which makes it easier to
read and can display more information on a single page). Most laptops have a screen that measures 12 to 17 inches
diagonally, while most PC monitors range in size from 16 to 22 inches or larger. If you have an old PC sitting around
gathering dust, you can convert it into a large display color scan tool at a minimal cost (typically $250 to $500 or less for
the software, including the interface cable).

25. Another advantage of using a computer as a scanner is that it can easily be updated by downloading the latest software
via the internet. This also can be done with most newer scan tools as well (using a PC as an interface with a USB cable).
The updates for DIY scan tools are often free, but for professional scan tools there is usually a fee or yearly subscription
to pay.
Dedicated scan tools, by comparison, are designed to be scan tools and nothing else. You cannot surf the Internet with
them or check your e-mail or Facebook page. They are for diagnosing cars only. Many professional-grade scan tools
have additional hardware circuitry and test leads that allow you to use the same tool as a multimeter or digital
oscilloscope to measure voltages, resistance and current. This is an extremely useful feature to have and reduces the
need for additional test equipment.
SCAN TOOLS WITH SCOPE DIAGNOSTICS
Many high end professional scan tools also have the added ability to
function as graphing multimeters or digital storage oscilloscopes.
Being able to display sensor voltages as waveforms makes it much
easier to detect problems that are nearly impossible to diagnose any
other way.
If you are looking for a multi-purpose tool that can be used as a
scanner, multimeter and scope, choose one that can display more
than one waveform at a time. Many professional scan tools can
simultaneously graph and display up to four different PIDs.
When a scope is hooked up to a sensor or circuit, it shows what is
actually going on inside that device or circuit. Voltage is displayed as
a time-based waveform. Once you know how to read waveforms, you can tell good ones from bad ones. You also can
compare waveforms against scan tool data to see if the numbers agree (which is a great way to identify internal PCM
faults).
A scope also allows you to perform and verify "action-reaction" tests. You can use one channel to monitor the action or
input, and a second, third or fourth channel to watch the results. For example, you might want to watch the throttle
position sensor, fuel injector waveform, crank sensor signal and ignition pattern when blipping the throttle to catch an
intermittent misfire condition.
Using a scope does require a working knowledge of scope basics as well as the limitations of the scope you are using.
Like scan tools, different scopes have different capabilities, so study and compare before you buy.
SCAN TOOL COMPARISON REPORT
For an up-to-date report compiled by the National Automotive Service Task Force (NASTF) on which scan tools are
required for which vehicle applications, Click Here .
If you would like to read one shop's experience with scan tools and why they own what they own, Click Here
To find out more about Aftermarket scan tool limitations, and the problems scan tool companies have getting current
service information from the vehicle manufacturers, Read This NASTF Report (January 2011).
WHICH SCANTOOL DO TECHNICIANS PREFER?
According to a recent (2011) user survey of 400 technicians by iATN (International Automotive Technicians Network), the
most popular scan tool form factors are as follows:
61% prefer a hand-held scan tool
28% prefer a laptop with scanner software
11% prefer a tablet with scanner software

26. Those who prefer a traditional hand held scan tool say the units are much faster and easier to use than a laptop or tablet.
However, many of the newest professional level scan tools are using Windows-based scanner software in a custom hand
held form (Snap-On Modis, Verus, Verdict, etc.). We will probably see more development of Windows scanner software
for tablets and custom apps for iPhones and other smart phones as time goes on.
ADVANCED SCAN TOOL DIAGNOSTICS
For advanced scope diagnostics, you will want to learn how to access Mode 06 information on a scan tool (most tools that
cost upwards of $200 can access Mode 06 today, but you have to know how to find it because it is not clearly marked.
Mode 06 data is the raw hexadecimal code data the engine computer looks at when it runs system monitors. This is
useful information to access when a vehicle is experiencing a no-code driveability problem, to verify whether or not a
particular sensor or circuit is operating within its specified MIN and MAX values, and to verify a sensor or other
component is working properly after it has been replaced.
Information on translating and converting Mode 06 hex code for Ford and GM can be found on the International
Automotive Technicians Network website (www.iatn.com). Go to the "Technical Resources" menu, then look in the Ford
and Toyota sections. The Mode 06 information is in a downloadable PowerPoint presentation by Paul Baltusis of Ford
Motor Company, called "An Introduction to Vehicle Networks, Scan Tools and Multiplexing."
OTHER THINGS YOU WILL NEED IN ADDITION TO A SCAN TOOL
When you buy a scan tool, don't expect to become a diagnostic expert overnight. All
scan tools have a learning curve, and it takes some time to figure out what the tool
will do (and what it cannot do), which PIDS and other sensor data you should be
looking at when troubleshooting different kinds of faults, and what the information
means.
Scan Tool Companion is a handy reference program that can help you make the
most of your scan tool. The program runs from a CD on a laptop or Desktop Windows
PC, and tells you which PIDs and data you need to look at by symptom, by code or by
system. It also includes background reference information on engine sensors, OBD2
monitors, OBD2 emissions testing, and the operation of the engine management
system. This is a "must have" reference program for any scan tool user.
Something else to keep in mind is that a scan tool by itself can't fix anything. It takes a brain to operate and use the
information provided by the tool. You need to be knowledgeable about OBD2, engine management systems and sensor
diagnosis. You also need access to current service information, technical service bulletins and electrical wiring diagrams.
If you do not know how a sensor or circuit functions, what causes a code to set, or how a particular sensor or circuit is
wired, how are you going to fix the fault?
You also can't rely on codes alone to identify all problems. Many problems never set a code. Some codes can be
misleading because of the combination of circumstances that caused them to be set. Other codes may be false codes
that never can be eliminated by normal repair procedures. You may have to reflash the computer to fix the problem.
The best advice here is to always check for TSBs, whether you find any codes or not. In many instances, there will be a
TSB that covers the problem and will save you hours of frustration.
Click Here to Look up Technical Service Bulletins for Your Vehicle
In conclusion, the more time and research you put into choosing a scan tool, the better satisfied you will be. Check with
your equipment suppliers or the sources listed below for specific product models, features and prices. Spend some time
on the Internet researching the various alternatives. Do your homework and you will find the tool (or tools) that are right
for you.