Diagnostic OBD2 Scanner

The vehicle diagnostic OBD2 scanner plug should be located within three feet of the driver and must be instantly accessible, meaning no tools are required to reveal the connection plug. It may be located underneath the dash or behind the ashtray, removable storage compartment or any simple hand removed cover. Cars and light trucks became mandatory in using the second generation OBD diagnostic interface system from the beginning of 1996 in USA. Other than the connector plug itself, the vehicle must have (unless removed by someone) an identification for OBD2 (OBD II) compliancy by means of a sticker or a tag plate under the hood.

European cars started using a similar system from January 2001 on gasoline engines and from January 2004 on diesel engines to monitor engine emissions. The European system name is EOBD2 which means Enhanced On-board Diagnostic System 2. The diagnostic OBD2 scanner or code reader plug is the same 16 pin shaped plug. The first system before the EOBD2 was the EOBD which stands for European On-Board Diagnostic. The EOBD system had no European stipulated standard and was different from manufacturer to manufacturer, in some cases the system also differed within the same manufacturer from one model to another.

Explanation of the Diagnostic OBD2 Scanner Plug Terminals
See Above Plug for Terminal number reference

• 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

There are three different second generation OBD software communications protocols. These are:

• SAE J1850 VPW (Variable Pulse Width Modulation)
• ISO 9141 Circuitry
• SAE J1850 PWM (Pulse Width Modulation)

Variable Pulse Width Modulation - SAE J1850
These are mostly likely found on GM cars and light trucks. This connector should have connector plug contacts in pins: 2 – 4 – 5 – 16 - BUT NOT 10

ISO 9141 Circuitry
These are commonly found on Chrysler vehicles, Asian imports and most European vehicles. This connector should have connector plug contacts in pins: 4 – 5 – 7 – 15 – 16

Pulse Width Modulation - SAE J1850
Ford vehicles utilize the SAE J1850 PWM system including Ford based vehicles like some Jaguar models (S-Type). This connector should have connector plug contacts in pins: 2 – 4 – 5 – 10 – 16

If your vehicle has this style connector, but doesn't have these pins populated, you probably have a pre-OBD2 vehicle, probably an OBD(1). Even having the connector with the contacts shown here is not an OBD2 compliant guarantee. This diagnostic OBD2 scanner connector has been seen on vehicle models before 1996, or end of 1995 and were not OBD2 compliant. The only sure way is by checking for the mandatory sticker or plate or checking with your local dealer through VIN identification.