OBD-II Diagnostic Scan Tool

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Frequently Asked Questions

Will it work on my car?
Where is the OBD-II Connector in my car?
What else do I need to use this?
How difficult is it to use?
Can it reset my Check Engine Light?
Can I write my own Scantool software for your scanner?

Will it work on my car?

All cars and light trucks built and sold in the United States after January 1, 1996 were required to be OBD II equipped. In general, this means all 1996 model year cars and light trucks are compliant, even if built in late 1995. Recently, a fifth protocol 'CAN' began appearing on a couple of models of 2004 vehicles. See below to be sure your vehicle has the pins present to work with this scanner.

There are two ways to tell if your vehicle is OBD II equipped:
1) There will be an OBD-II Connector in the drivers area.
2) The under the hood emission sticker /owner's manual will say "OBD II compliant" or "compliant with OBD-II Diagnostics".

Here is a layout and pin out of the OBD connector found in most cars. The connector can be found in the driver’s area of the vehicle.

Pin 2 - J1850 Bus+
Pin 4 - Chassis Ground
Pin 5 - Signal Ground
Pin 6 - CAN High (J-2284)
Pin 7 - ISO 9141-2 K Line
Pin 10 - J1850 Bus
Pin 14 - CAN Low (J-2284)
Pin 15 - ISO 9141-2 L Line
Pin 16 - Battery Power

On 1996 and later vehicles, you can tell which protocol is used by examining the OBD-II Connector:

CAN -- The connector should have contacts in pins 4, 5, 6, 14, and 16.
J1850 PWM -- The connector should have contacts in pins 2, 4, 5, 10, and 16.
J1850 VPW -- The connector should have contacts in pins 2, 4, 5, and 16, but not 10.
ISO 9141-2 -- The connector should have contacts in pins 4, 5, 7, 15, and 16.
ISO 14230 -- The connector should have contacts in pins 4, 5, 7, 15, and 16.

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Where is the OBD-II Connector in my car?

SAE standard J1962 mandates the location of the OBD-II connector as follows:

Consistency of Location – The vehicle connector shall be located in the passenger compartment in the area bounded by the driver’s end of the instrument panel to 300mm beyond the vehicle centerline, attached to the instrument panel, and accessible from the driver’s seat. The preferred location is between the steering column and the vehicle centerline. The vehicle connector shall be mounted to facilitate mating and un-mating.

Ease of Access – Access to the vehicle connector shall not require a tool for the removal of an instrument panel cover, connector cover, or any barriers. The vehicle connector should be fastened and located so as to permit a one-handed/blind insertion of the mating test equipment connector.

Visibility – The vehicle connector should be out of the occupant’s (front and rear seat) normal line of sight but easily visible to a “crouched” technician.

Bottom line here….. it should be somewhere in plain sight under the drivers dash area.

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What else do I need to use this?

To use the OBD-II Diagnostic Scanner, you need a computer or laptop with the following:

486DX-33 or faster IBM PC Compatible Computer
Windows 95, Me, Xp, or 2000 Operating System
15 Mb free disk space
Video – 800x600 or higher
Windows Compatible Printer
DB9 Serial Port capable of 57,600 baud with CTS available or USB to RS-232 adapter

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How difficult is it to use?

The system is very straight forward to use. One cable connects from the scanner to any available serial port on your PC, the other from the scanner into the OBD-II port on your car. Start your car and about 10 seconds later, the scanner has initialized communication automatically. Start the Diagnostic Scanner program on your PC and the program automatically starts communicating with the vehicle and shows you the current status of the Check Engine Light (MIL) and the Monitor Test Results. From here, most information is just a click or two away.

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Can it reset my Check Engine Light?

Yes, and a whole lot more. Resetting the Check Engine Light (MIL) is just two clicks away after starting the OBD-II Diagnostic Scanner program. Go to the product page to see a list of all features.

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Can I write my own Scan tool software for your scanner?

Absolutely, for a complete description of the interface protocol, see the OBD-121 data sheet and the OBD-121 Sample Application. If you come up with something, send it to me and I'll post it for others to try.