Firstly, OBD-II is an upgrade, from the original system, in earlier vehicles.
With advancements in technology, came improvements and the second generation system was introduced.
As a result, they all use a, standardized digital communications port, that provides real-time data. This results in, much faster diagnostics, of a vehicle’s problem.
In addition, if a problem or malfunction is detected, the OBD-II system, illuminates a warning light. Consequently, this warning light will display the phrase; “Check Engine” or “Service Engine Soon”. Furthermore, the system will store information, about, any detected malfunctions.
Firstly, the OBD-II on-board computer features, a 16-pin port, located under the driver’s side dash. Furthermore, it allows a mechanic or anyone else; to read the error code, using a special scan tool.
So, What should I do if the warning light comes on?
Consequently, there are many problems that, can cause the light to illuminate. So, it is hard to generalize, how severe a problem may be. Additionally, there are other malfunctions, that can cause the warning light to blink. The reason any OBD-II scan tool can read the codes is, because of the standardized pinout.
The standardized pinout is as follows:
- Pin 1: Used by manufacturer
- 2: Used by SAE J1850 PWM and VPW
- 3: Used by manufacturer
- 4: Ground
- 5: Ground
- 6: Used by ISO 15765-4 CAN
- 7: The K-Line of ISO 9141-2 and ISO 14230-4
- 10: Used only by SAE J1850 PWM
- 14: Used by ISO 15765-4 CAN
- 15: The K-Line of ISO 9141-2 and ISO 14230-4
- 16: Power from the car battery

In other words, OBD-II scanners can connect to these ports and identify the engine codes; from any manufacturer that uses one of the OBD-II protocols.
It not only controls, engine functions, but also monitors, other vehicle components like:
- Engine Misfires.
- Emissions Control Systems.
- Vehicle/Speed Idling Controls.
- Computer Systems.
- Transmission Systems.
- Seat-belt, Airbags.
- Vehicle Body & Chassis.
- Accessory Devices.
- Variable Valve Timing.
Finally, the diagnostic control network of the vehicle. It also follows, the California Air Resources Board (CARB) guidelines; for data storage and accessibility to be provided to the external scan tools. Thus, OBD-II is a protocol for vehicle diagnostics communication.
Choose Your OBD-II Help Topic Below
P0001 Through P0099 – OBD-II Trouble codes, fuel and air metering.
P0100 Through P0199 – OBD-II Trouble codes, fuel and air metering.
P0200 Through P0299 – Fuel and air metering (Injector Circuit).
P0300 Through P0399 – Ignition system or engine misfire.
P0400 Through P0499 – Auxiliary emissions controls.
P0500 Through P0599 – Vehicle speed and idle control system.
Diesel Engine, Common Check Engine Light, Diagnostic Trouble Codes
P0008-U1601 – Dodge Cummins, diagnostic trouble codes.
P0100-P0804 – Chevy/GM Duramax, diagnostic trouble codes.
P1111-P1783 – Ford Power-stroke, diagnostic trouble codes.
Thank You !