Skip the auto shop - Our mechanics make house calls

Q: How do I know that my OBD system is working right?

asked by on

How can I tell that my OBD system is working right?

A: The OBD system on your vehicle is a self-mo...

The OBD system on your vehicle is a self-monitoring system. The Powertrain Control Module monitors and controls all of the systems and functions that regulate fuel, ignition, emissions, and engine cooling as well as having some minor control over air conditioning, traction control, and others. The way that the driver is informed of any malfunctions in the OBD system is through the Malfunction Indicator Lamp (MIL) or Check Engine light.

To verify that your OBD system is working normally, put your key in the ignition and start the engine. Watch the instrument panel for the Check Engine light. When you start the engine, the MIL should illuminate for several seconds. This occurs to verify that the PCM is checking all of its systems, components, and circuits for proper operation. After several seconds have elapsed, the MIL should go out. This verifies that the OBD system on your vehicle is working normally.

If the MIL does not illuminate, or comes on and stays on, then you need to have a trained technician like those at YourMechanic take a look at your vehicle. Checking the status of your Check Engine light could be as simple as a burned out bulb to something more involved such as an issue with the computer itself.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Advice on buying a scan tool

No, I can't think of one that would go for under 500 dollars. If you are talking about the ones that are bi-directional and have a built-in scope, these things start at 1,500 up to 12,000 dollars. For the scopes,...

Q: Is diagnostic fee applied to repairs

The diagnostic service fees are not included in the service call. If a diagnosis is needed to find out the problem then the mechanic needs to be compensated for their time to do the diagnosis service.

Q: Does the OBD System Measure Gases in the Car's Exhaust?

The onboard diagnostic (OBD) system utilizes sensors mounted in the engine exhaust stream to measure the amount of oxygen that comes out of the engine after the combustion process. When an engine intakes a certain amount of air into the...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...