What exactly is OBDII?

Question

Guess I'm too old. I retired two years ago and just got back into auto mechanics for the sake of my 16 year old grand son. Many old things still apply, I've learned a great deal about the newer vehicles, but I've still got a lot to learn

Answer 1

On Board Diagnostics Two is the entire electronic monitoring system that ensures that the engine is running at pollution standards. It's main purpose is to ensure that there is not a spike in engine emissions. OBD (models1982-1989), OBD-I(models 1990-1995), and OBD-II(models 1996-present) both have a device called an ECM or Engine Control Module. This module is connected to all the sensors that are in the engine. Without this module installed, your engine will not function at all. On the dashboard there is also an MIL (Malfunction Indicator Light) or also known as "Check Engine" light. Whenever this light comes on, it means that the ECM has detected an engine malfunction. These malfunctions could range from simple things, such as leaving the gas cap door open, to more complex issues, such as a misfire on all cylinders, or a burned out Oxygen sensor. An MIL could also affect driveability and cause sluggish performance. But in order to pinpoint the problem, you'll need to connect an OBD-II ECM Scanner to your car's OBD-II Port. The scanner will give you a malfunction code and tell you what has failed in the engine. In California, MIL's need to be fixed in order to pass state smog tests. In all, OBD-II is a very important part of your car.

Answer 2

MIKE C gave it to you pretty good. The only thing I would add to that is that OBD II also provides for some system monitors that are not computerized.
An example is the catalytic converter, or the fuel cap. Neither are computer components, but they must be monitored. Therefore the vehicle must be driven in a certain manner for the monitors to be complete.
Also, the "Check Engine" light (now referred to as the MIL - Malfunction Indicator Light) must only be illuminated when there is a failure in a system monitored by the PCM that has the potential for emissions to rise to more than 1-1/2 times the MAX prescribed levels.
For a clearer discussion of OBD II, Go here------->

http://www.aa1car.com/obd2help/

and here-------->

http://www.obd-codes.com/trouble_codes/index.php

...for some good definitions.

As you run into the system more and more, try to keep one thing in mind. When you get a code for a particular system, remember it is for the circuit or system, not NECESSARILY a specific component. Use the code description as a starting point for your DIAGNOSTICS.
If you have any other questions concerning this little protocol, E-Mail me. I will be glad to help where I can.

Good Luck

Answer 3

On-Board Diagnostics, or OBD, in an automotive context, is a generic term referring to a vehicle's self-diagnostic and reporting capability. OBD systems give the vehicle owner or a repair technician access to state of health information for various vehicle sub-systems.

OBD-II is an improvement over OBD-I in both capability and standardization. The OBD-II standard specifies the type of diagnostic connector and its pinout, the electrical signalling protocols available, and the messaging format. It also provides a candidate list of vehicle parameters to monitor along with how to encode the data for each. Finally, the OBD-II standard provides an extensible list of DTCs. As a result of this standardization, a single device can query the on-board computer(s) in any vehicle. This simplification of reporting diagnostic data led the feasibility of the comprehensive emissions testing program envisioned by the CARB.

Follow this link for a full description:
http://en.wikipedia.org/wiki/OBDII

Answer 4

I had to go buy an OBDII plug in for my car. It's about 90$, but it comes with a helpful booklet that will tell you what the codes mean and the 1st, 2nd, 3rd choice of action for the code. It's hard to get any help short of taking it to the dealer for any weird codes. If you're getting back into fixing cars, I would go buy one because everything is run by a computer nowadays

Answer 5

OBD II is "On Board Diagnostics 2nd Generation" Just new computer programming, that all hand held diagnostic machines can comunicate with, and the car's computer has more things to be able to control on the car.

Answer 6

ON-BOARD DIAGNOSTICS II. It came into being to standardize vehicle diagnostics for every make and model. Before obd2 you had to have sp. equip. and training for every different car, which can cripple an independant shop.