What is OBD-II

OBD-II and Digital Vehicle Management
By Ali Shoja
Final Draft
This white paper looks into how the introduction of Onboard Diagnostics II (OBD-II) has simplified diagnosing
car problems and as well as improving reading and writing from/to vehicle’s Electronic Control Unit. OBD-II
systems have also played a large role in reducing emissions and costs for both consumers and manufacturers by
simplifying maintenance and using a standardized system.
Summary ................................................................................................... 1
What is OBD-II
Market Drivers .......................................................................................... 3
The Market
Mobile Applications for OBD-II Vehicles
Large Business Demand
Historical Approach ................................................................................... 6
A Revolutionary Step towards Digital Engine Management
Solutions .................................................................................................. 10
The Problem
Solution, Benefits and Features that OBD-II Offers
Conclusions .............................................................................................. 13
Future of OBD System
For More Information .............................................................................. 16
What is OBD-II
With the advent of computer software and increasing use of
technology in the last decade on new vehicles, it has become very
common for consumers and small auto shop businesses to perform what
is known as a digital vehicle diagnostic. This is basically just scanning a
vehicle with symptoms of powertrain problem (check engine light) with
a type of electronic device known as an OBD-II scanner. This process
can be done on many kinds and brands of vehicles because since 1996 all
vehicles have been equipped with OBD-II engine management system
(Santini). The OBD-II system was originally developed to provide
vehicle diagnostics and emission control. However it actually played a
bigger role in the emission testing sector and was armed to detect any
breakdowns in a car’s emission control system. The troubleshooting
properties of ODB-II was more of a side benefit of this system and it
allows technicians to troubleshoot vehicle problems. The OBD-II system
on the car is basically accessed via a 16 pin serial data connector type.
Serial data is a type of connection that works by sending series of pulses
of data in sequences or at a time to the scan tool. Scan tool is generally a
computer that has an OBD-II connection and software and therefore can
read or even write to the on board ECU (NAPA). These scan tools can
collect a very large amount of data through the OBD 2 port. This data
provided through the OBD-II port is referred to as Parameter Identifiers
(PIDs). PIDs are entered by the user of a scan tool (DeMay). These PIDs
provide information or status about various sensors installed in the car.
For example there is a PID for displaying water temperature. This PID
which is just a hexadecimal code can be entered by a scan tool user and
it will receive a meaningful value in response. This means that almost
anyone with an OBD-II reader has the ability to scan and read wealth of
information from his/her car. This has recently caused an explosion in
various OBD-II reader software and hardware in the auto industry. For
example Linear-Logic has developed a device called a ‘Scangauge’ that
can be installed on any OBD-II equipped vehicle to provide information
such as fuel consumption and various other information. It will work by
reading some standard ECU information by sending hexadecimal code
and receiving meaningful values back for the driver (Scangauge). This is
however just a reader and does not allow writing or modification to the
Electronic Control Unit (ECU). For writing to an ECU, there has been an
increasing trend in use of combination of hardware and software
developed by a tuner company for a specific brand of vehicles. Along
with an OBD-II serial to USB cable or to Bluetooth, one can easily
read/write data to a vehicle’s ECU using a tuning software. There are
various premium softwares available for purchase but there has been a
recent growth in open source software such as one called EcuFlash. This
software is made to work with Mitsubishis and Subarus only (Tactrix).
According to developers of EcuFlash, this software works by use of an
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XML language definition file that has been developed for that particular
car’s ECU. This definition can be made by anyone with enough
experience in XML coding and knowledge in understanding hexadecimal
values. Also Romraider is another open source software which can be
used to modify ECU files, but it does not directly write to an ECU
(Romraider). This software also requires an XML definition file before it
can read/write to an ECU. The OBD-II interface on vehicles allow a cost
effective and efficient modification by open source software. There are
paid software and expensive scan tools that have the ability to read/write
to an ECU but these are usually very expensive. In the end whichever
type of software or hardware is on hand, the OBD-II interface must be
present on the car and it is the only way to access a car’s ECU.
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Market Drivers
The Market
The biggest attraction for ECU modification on modern cars is the
need to increase performance and or diagnose a problem with the car.
However the audience for the OBD-II reading system is much larger.
With the growing advent of OBD-II emission tests vs your traditional
exhaust tailpipe the demand for OBD-II reader software and hardware
has skyrocketed (Cope). The current market for OBD-II readers and
ECU modification software is small. Especially for Open Source tuning,
there are only a handful of software available out there but it will
continue to grow. One of the reasons why this is likely is because there
are now many companies out there that will sell OBD-II scanners and
coders and with advent of technology, this has become a fairly cheap
ordeal. One can expect to pay between $200 to about $500 dollar for a
good OBD-II scanner or reader. Since OBD-II is standard on all vehicles,
it can work on any other vehicle that one would purchase in future. An
average cost of getting your vehicle scanned at an auto shop is about $40
in Canada and so the savings can accumulate in a short time span (Len
G.7.). This is not to mention the wealth information that you can gather
from your car such as average fuel consumption or battery voltage. Some
type of scanners like the Scangauge II we mentioned previously can be
used while the car is moving/operating to display data. This device then
basically can be used as an extra set of gauges to help deliver
information to the user as well as scanning codes and resetting check
engines (Scangauge).
Scangauge II OBD-II Reader/Scanner
Mobile Applications for OBD-II Vehicles
Even though the Market for such devices is still young, there has
been a growing development of such standalone OBD-II devices
equipped with software that can communicate with the ECUs. Yet there
are growing methods of collecting information about your car using the
OBD-II interface. Actron which is a company that works on providing
repair and diagnostic equipment is releasing an application for mobile
devices that allows users to perform vehicle diagnostics using their
smartphones. This works by wirelessly connecting to the OBD-II serial
port using Bluetooth. According to Jennifer Grabowski who is the
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product manager of U-Scan (part of Actron company), “The U-Scan and
mobile app is the next generation in vehicle diagnostic wireless
technology at a fantastic price point, Moreover, the app is fully
upgradeable. Users can add available key features they have come to
expect from Actron diagnostic tools" (Actron to Release U-Scan to
Enable Vehicle Diagnostics Using a Smartphone). There are also other
available applications for mobile devices that can provide diagnostics
and report ECU data using the OBD-II port. These Applications are
available for both the iPhone and Android mobile devices. One of these
applications is called ‘Torque Pro’. This application provides similar
information as other OBD-II readers for android devices (Torque OBD2
Torque Pro Application on a Nexus Phone Displaying Various Gauges
This application for example can allow a user to view multiple gauges at
the same time. These gauges work similarly to other standard OBD-II
scanners by sending a PID to the ECU and translating the response to an
understandable value for the user. The PID are selected by user of the
mobile device in simple terms such as “Boost” or “Throttle” (Torque
OBD2 Wiki).
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Large Business Demand
Aside from use for average consumer, OBD-II readers are also
gaining popularity with large corporations such as auto insurance groups.
Progressive, a large insurance company based in United States, is now
offering discounts to customers who allow the company to record their
driving behavior. Glenn Renwick, president and CEO of Progressive has
said, “Get a quote from Progressive and send us a 'snapshot' of your
driving habits, and see what happens. At worst your rate stays the same.
But you could end up saving up to 30 percent on your car insurance”
(Marketing Weekly News). This snapshot system progressive is talking
about is basically a wireless OBD-II reader that uses wireless internet to
send ECU information such as throttle opening and speed to progressive.
After thirty days the insurance company customer can login and check
the discount that they are now eligible for based their driving behaviors
(Marketing Weekly News). However one must keep in mind that these
companies are only generating demand and there are other OBD-II
businesses who manufacture these devices are really getting the financial
benefits. IOSix, which is a company that develops OBD-II Dataloggers
is one of the potential suppliers to large corporations like Progressive. In
their product information of their OBD-II Datalogger, IOSix claims that
their device can monitor everything that is happening to a large fleet of
vehicles. This logger allows for easy installation since every vehicle past
1996 has OBD-II interface and also is equipped with a GPS chip, WiFi
and Cellular data to transmit information. This is exactly something that
Progressive is looking for since they are such a large corporation with
lots of vehicles owned by their many customers ("OBD-II/CAN
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Historical Approach
A Revolutionary Step towards Digital Engine Management
OBD-II interface in cars is revolutionary and with advent
technology now in smartphones, it allows us to collect a massive wealth
of information for our cars. In the past it used to be that in order for a
person to diagnose a check engine light, one had to take the car in to an
autoshop. After possibly a long time of wait and expensive payments, a
mechanic would identify a code reported by the ECU using an OBD-II
reader. Now however anyone can read diagnostics codes thrown by the
car’s ECU using a mobile app along with an OBD-II wireless dongle.
This is also a testament to both the Canadian and US government making
OBD-II interface mandatory on cars starting in 1996. Had they failed to
do this it would have been impossible right now to develop a
standardized ECU scanner. The current OBD-II connection is a standard
16 pin port standard on every vehicle. OBD-I which was only there to
alert of a system trouble was primitive in design and also had no
emission control or standard test procedure (NAPA).
It would have been impossible for companies like linear logic and
IOSix to develop tools such as scangauge and dataloggers. This would
mean that regular car owners would not have the ability to self-diagnose
their vehicle and to also take advantage of possible insurance rate
decrease. Going back further in time, before the use of computers,
mechanics had very little to start with when diagnosing cars (Hartman).
One had to check for problems only based on symptoms or sometimes no
evidence at all. The OBD-II system now has become tremendously
helpful in helping to diagnose breakdowns and problems with use of
computer, providing codes that can pinpoint exactly where the problem
is. Without this system, applications such as Torque pro and devices
such as Scangauge II would not exist now.
Aside from reading and scanning ECUs, there is also the Writing
factor. Some car enthusiasts like to modify their car’s ECUs to perform
in certain ways, usually to increase power and or to calibrate ECU for
certain modifications. For example Edlebrock Company has developed
an ECU writer or flasher called eForce that lets the enthusiast to
supercharge his/her vehicle while having the ECU calibrated for the
extra added hardware. Since all of the 1996 and later vehicles are
equipped with digital OBD-II systems, with use of table based software
logic one can easily modify many engine parameters or even actually
add to it (Hartman).
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ECU Flash port device (Hartman)
Hondata (a Honda tuning company) offers a software and hardware
combination package that can help make some Honda ECUs
programmable on Hondas that have the OBD-II compliant engines
While there are various auto tuning companies that offer software
and hardware for sale to help flash a factory vehicle’s ECUs, there has
been some growth in the Open source market. As mentioned before,
Tactrix Company which offers EcuFlash software along with their
Openport 2.0 OBD-II dongle is an opensource software provider for
Subaru and some Mitsubishi vehicles. According to them, flashing is
very easy, “rom reflashing to logging to diagnostics, the Openport 2.0
can do it all with just a PC laptop and a USB port” (Tactrix). The
software they offer is free to download and works with virtually any
windows machine. It is also fairly easy to understand and an average car
enthusiast can very quickly adapt to its functionality. However before
OBD-II systems were present, it was very difficult to access the car’s
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ECU, let alone modifying it. Previously, there were five methods
available in tuning an ECU. All of these methods were part of a
complicated process called piggybacking. There are five methods to
piggybacking. Firstly one could brainwash the ECU or by having the
ECU read data off a separate computer memory. Second method is
disobeying the ecu which is basically modifying signals sent by the
computer. Another method would be to the ECU read made up signals
from the sensors on the car. Fourth method is to ignore the main ECU
and have an auxiliary one installed that will take care of required
functions that are to be modified. Final method in modifying a nonOBD-II ECU would be to help the ECU by having separate controllers
enhancing engine performance based on engine status (Tactrix)
As it is evident, it used to be very difficult for one to manage
their ECU before the existence of OBD-II systems. Also open source
software is making it very easy for a car owner to modify their engine at
an economical price. With current OBD-II systems a simple laptop with
available USB ports and an OBD-2 adapter is often enough for one to be
able to modify ECU content.
A staggering amount of wires and computer chips were needed to modify ECUs before
OBD-II (Hartman)
In the past it used to be that Insurance companies had to totally rely on
historical data on average person’s driving style in a certain geographical
area to calculate premiums. It is basically common knowledge now that
depending on the area and the type of car you drive your insurance rates
can vary. However what if a certain person falsely falls into a high risk
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category because he/she drives a sports car in a generally accident prone
neighborhood? This person could be a very skilled and law obeying
driver. This is basically where OBD-II readers come into play and help
insurance companies to determine whether or not this person is a
cautious driver or not. This is a more reliable method of identifying high
and low risk drivers than just generalizing a geographical area and
vehicle types.
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The Problem
The biggest problem with car diagnostics, ECU read/writing is the
lack of OBD-II interface system on most pre-1996 cars. This effectively
means that most of the process of reading, writing to ECUs is impossible
on such vehicles. Unfortunately the only solution to this problem would
to sell and buy vehicle equipped with a digital engine management
system such as OBD-II. This system allows for excellent flexibility to
performing read/write functions as well allowing one to perform
emission tests at a cheap rate.
Solution, Benefits and Features that OBD-II Offers
Since OBD-II system allows reporting and access to all emission
management systems, most states in United States and provinces in
Canada now only perform emission tests by scanning for any powertrain
problems which is usually indicated by a check engine light (Santini).
This type of emission testing is very beneficial because it saves costs.
There is no need to spend time with equipment designed to measure
emissions at the tailpipe. OBD-II systems can report problems now
which a technician can detect using an OBD-II scanner. A recent study
by the Environmental Protection Agency in United States determined
that the overall success rate of OBD-II based emission testing was over
98%. It was also found that the time it takes to complete an OBD test is
less than five minutes. This type of emission testing also led to less type
of ‘ping pong’ repairs or wasteful and time consuming repairs that do not
solve emission problems. Evaporative problems can be very easily be
detected by OBD-II systems as well. Also the repairs required by this
type of system are much easier than those required by tailpipe testing
Aside from providing emission testing benefits, OBD-II systems
provide easy ability to read reports from ECUs as mentioned before.
There are sometimes problems with vehicles that happen intermediately,
or unexpectedly. This sort of problem is often very hard to solve because
it almost never shows up at the dealership by some unlucky chance.
However recent OBD-II readers now have the ability to freeze or to
capture a snapshot of the ECU at the moment the problem has occurred.
This snapshot could later be scanned by a technician so the problem with
vehicle can be identified This reduces chances of other problems
occurring such as accidents, which is common because often a technician
is distracted a small OBD-II scanner screen while driving. Therefore the
freeze features of affordable OBD-II readers make it easier to capture the
data and then have it analyzed at the shop (Anderson).
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OBD-II readers provide the ability for any car owner to perform
do it yourself problem solving with their vehicle. For example the Innova
3100 reader is a cheap way of doing such functionality. This device is
similar to Scangauge II but it differs in a way that it is not used as a
gauge, instead as a code reading diagnostic tool only. A do it yourself
solution is now looked at as a fairly complex problem for modern car
drivers. This is not surprising given the amount of complicated
accessories and features that manufacturers have added on since the
1970s. It used to be that ODB-I system only covered about 30% of
vehicle’s components operation, but now OBD-II can cover up to 85% or
more of such components. So armed with an OBD-II reader like the
Innova anyone can easily diagnose a check engine light. Firstly, the
device is only controlled with a simple and clean use of 5 buttons. This
makes the interface easy to use and understand without a confusing look
and feel of button overload. This type of design is very common on
OBD-II readers and seldom can more than 4-5 buttons be found on the
entry level OBD-II readers. This easy to use device just needs to be
plugged into the OBD-II port found under most steering wheel sections
upon which time it will then download the required diagnostic
information. The Innova system is affordable at $150 discounted price
and the savings can quickly add up over time for a car owner after some
years (Williams).
Datalogging is another feature of OBD-II interface. As explained
before, datalogging is useful when an owner or a fleet owner wants to
find information about the vehicle’s specific location, performance or
behavior. This is in common use with rental car or insurance companies.
Previously we explored that use of dataloggers can help customers save
money on their insurance premiums by proving their good driving
behavior to insurance companies. Aside from lowering costs for drivers,
Datalogging can also help enthusiasts in correctly modifying their ECU
to carry out certain tasks. For example after an engine modification has
been carried out, a road driving session can be carried out while have a
computer logging powertrain performance using a laptop connected to
the OBD-II interface. This can ensure an optimal and smooth tuning of a
system and prevent failures due to unsafe tuning. These logs can then be
analyzed at home for possible problems (Hartman).
Another important benefit of OBD-II system is the solution it
provides to performing modification to ECUs in order to manage the
powertrain. The OBD-II system as mentioned before allows access to
over 85% of sensors installed in the vehicle. With such wealth of
information, it is only too easy to perform a serious ECU modification.
This modification can be carried out by using any of the devices
mentioned before. Open source tuning is good cost effective option
because it is free to download. The only cost associated with open source
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tuning is the cost of the OBD-II to USB dongle that must be purchased
from the open source software developers, ie. Tactrix open port 2.0
(Tactrix). The EcuFlash software that works with Tactrix opensource 2.0
is fairly easy to use. Once this software is run it’s easy to navigate across.
Most of the ECU’s hexadecimal code has been converted to an XML
table format which is very easy to understand by an average user. The
data from such tables can easily be modified by an average user.
Fuel Table from ECUFlash
Apart from being easy to use, new OBD-II ECU tuning software
has simplified engine management. It can provide behaviors such as
disabling check engine light thrown by specific codes or adding
functionality such as sending signals in order to increase ignition timing
and fuel to boost power. Also car functionality such as disabling certain
alerts or alarms (door ajar) can be added to a vehicle using ECU
modification. Overall this is a much more ‘plug and play’ method than
using the piggyback method discussed in previous section. Piggybacking
involves to actually modify a hardware inside a vehicle and or to add to
it. This process is often very complicated and can’t be followed by an
average car enthusiasts. Piggybacking is also expensive because it is
unique to each brand and model of car and requires lots of hardware and
time. The only problem associated with ECU modification using the
OBD-II interface is possible damage to system caused by inexperience or
nulling of a vehicle’s warranty. Most car manufacturers nullify the
warranty if unauthorized vehicle modification is found (APR) (Taxtrix).
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Future of OBD System
The introduction of the OBD-II system in the mid-1990s has played a
significant role in the diagnostics and ECU modification sector of the
auto world. Especially with the ever growing use of wireless devices and
smartphones, growing number of developers have created applications
designed to work with OBD-II systems to provide users with information
regarding their vehicle. The creation of standardized PIDs for OBD-II
system means that any scanner programmed with same code to find a
specific sensor information such as water temperature can work on any
OBD-II vehicle. This flexibility for OBD-II readers allows for extreme
ease of use due to the cross compatibility among any vehicle. Therefore
one manufacturer can create an OBD-II reader or Gauge that will work
on any OBD-II vehicle. Since OBD-II became a mandatory standard in
United States and Canada it means that almost every vehicle developed
since 1996 has the ability to provide OBD-II digital engine management.
OBD-II readers and scan tools are now vital among car technicians to
diagnose problems with vehicles. Every shop dealership has one and
since there are a lot of cars on the road, this means a lot of OBD-II
hardware and software must be created in near future.
There are over 100 OBD-II Apps available on GooglePlay (Android App)
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OBD-II sensors play a vital role in ECU modification field as well and
allow for communication between a laptop and vehicle’s ECU. The
memory on board of an ECU can be modified by a user easily using easy
to understand software. There are also various tools available from
standalone physical ports to software and hardware package ranging
from zero to nearly one thousand dollar in cost. ECU modification has
become much more simplified due to OBD-II systems and use of
expensive complicated piggyback systems can be now avoided.
Emission testing has also been very simplified with introduction of
OBD-II interfaces. In fact OBD-II system’s main goal was control of
emissions in addition to providing good diagnostic information. Cars
equipped with OBD-II systems are now very easy to maintain and their
evaporative systems can be monitored by checking sensors such oxygen
sensor voltage and compares them to set of normal data (Cope).
However as time passes and OBD-II system is quickly aging, calls
for a better OBD-III system have been growing. While OBD-II systems
store diagnostic and other vehicle problems offline, it has been proposed
that the new OBD-III system should report problems immediately using
a Satellite connection. This would eliminate the need for regular 2 year
emission tests as only vehicles with check engine light would be
immediately identified as well as notified to perform an emission test.
Therefore the biggest aim of OBD-III system is cost cutting. However
there are possible problems with use of OBD-III systems in near future.
One of those problems is invasion of privacy. Since your vehicle is now
remotely connected to an outsider, its information such as speed and
location can easily be monitored. A memory chip which basically records
information reported by the GPS chip, speedometer and various other
sensors uploads these information using either Wi-Fi or mobile data. An
outsider such as a police officer could monitor this information and
possibly issue a ticket. If this happens one has very little chance of
explaining and defending this situation (Fraser).
Whatever the next OBD system upgrade brings, it should be accepted
that with ever increasing technology in both hardware and software,
OBD-III will be also revolutionary. Aside from controlling emissions and
speeds, particular attention should be paid to standardization and
customizations of the ECU. Currently every manufacturer uses OBD-II
interface, however their ECU software and hardware designs are
completely different. As we mentioned before softwares such as
EcuFlash are solely designed for specific cars (Subarus). So a software
designed for tuning Subaru ECUs is not compatible with that of a
Volkswagen. Standardization of the ECU software could even further
simplify diagnostics by allowing the same PID codes to be used on all
vehicles to receive the same information. Also it will be much easier to
hire developers for auto companies to create ECU software, as one
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language or software architecture becomes common for all car
It must also be remembered that not all electronics and software are
full proof and especially in case of cars where mechanics are involved,
the system must be designed in a way that is easy to understand and to
repair without the need for a degree in computer engineering. Overall
the introduction of the OBD-II system significantly simplified vehicle
diagnostics, reading and writing to ECUs and as well as controlling
emissions, all with a use of simple but powerful software and hardware.
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For More Information
Santini, Al. OBD-II: Functions, Monitors and Diagnostic Techniques.
Delmar Publishers, 2010. Print.
DeMay, Rod . "Vehicle monitoring system." PatentUS 20080133067
A1. (2008): n. page. Web. 1 Apr. 2014.
googleapis.com/pdfs/US20080133 67.pdf>.
Cope, D. "On-Board Diagnostics II (OBDII) ."Environment Canada.
(2004): n. page. Web. 1 Apr.
<http://www.ccme.ca/assets/pdf/jia_ trnsprt_obd_e.pdf>.
Len, Henry. "Buying code reader can help diagnose car
problems." Gazette [Montreal] 26 Jul 2003,
G.7.. Print.
"Actron to Release U-Scan to Enable Vehicle Diagnostics Using a
Smartphone." Manufacturing Close
Up. (2013): n. page. Web.
1 Apr. 2014.
"Torque OBD2 W iki." http://torque-bhp.com/wiki/Main_Page.
(2014): n. page. Web. 1 Apr. 2014. <http://torquebhp.com/wiki/Main_Page>.
"Property and Casualty Insurance Companies; Good Drivers F inally
Get the Savings They Deserve as
Progressive Unveils SnapshotSM
Discount Countrywide."Marketing Weekly News. (2011): n.
Web. 2 Apr. 2014.
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"OBD-II/CAN DATALOGGER." IOSix. IOSix, n.d. Web. 2 Apr 2014.
<http://iosix.com/OBD-II Datasheet.pdf>.
“OBD II and You.” Anderton, Jim
S S G M, Service Station & Garage Management; Jun 2006; 36, 6;
pg. 26
W illiams, Paul. "Unlock Your Car's Secret Codes." The Ottawa
Citizen: 0. Apr 18
2003. ProQuest. Web. 3 Apr. 2014 .
Fraser, Brock, and Jennifer Fraser. "OBD III - the proposed future of
On Board Diagnostics." Hot Rod Oct. 1998: 22. Canadian
Periodicals Index Quarterly. Web. 3 Apr. 2014.
"Tactrix." Tactrix. N.p., n.d. Web. 3 Apr 2014.
"Romraider." Romraider. N.p., n.d. Web. 3 Apr 2014.
< http://www.romraider.com/Documentation/TuningFAQ / >.
"Romraider." Romraider. N.p., n.d. Web. 3 Apr 2014.
< http://www.romraider.com/Documentation/TuningFAQ / >.
"Scangauge." Scangauge. N.p., n.d. Web. 3 Apr 2014.
< https://www.scangauge.com/>.
"APR." APR. N.p., n.d. Web. 3 Apr 2014.
< http://www.goapr.com/support/chip_tuning_faqs.html>.
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