Read your car’s mind: what a cheap OBD2 scanner tells you
The check engine light is not a mystery. A simple scanner reads the fault code in seconds, so you know whether it is a loose fuel cap or a trip to the garage.
The check engine light causes more worry than almost any other dashboard symbol, mostly because it tells you nothing on its own. A basic OBD2 scanner changes that. Plug it in and the car tells you what it thinks is wrong.
What OBD2 is
On-board diagnostics, second generation, is a standard port and set of codes found on cars sold in the United States since 1996, and on most cars elsewhere from the early 2000s. The port is usually under the dashboard on the driver’s side, within reach of your knees.
How to read a code
- Turn the car off and plug in the scanner.
- Turn the ignition on, or start the engine if the scanner asks you to.
- Read the stored codes. They look like P0420 or P0171.
- Note them down before you do anything else.
Decoding the letters
- P is powertrain: engine, transmission, emissions. The codes you will see most.
- B is body, C is chassis and U is network communication.
- A 0 after the letter means a generic code that means the same on every car. A 1 is manufacturer-specific.
Solid or flashing?
A steady light means the car has found a fault and wants it looked at soon. A flashing light usually means a misfire that can damage the catalytic converter. Reduce speed and get it checked as soon as you safely can.
Do not just clear it
Scanners can erase codes, but that does not fix anything. Clear a code only after you have fixed the cause, then watch to see if it returns. And bring your codes to your mechanic; a conversation that starts with the exact fault is quicker and cheaper for everyone.
