If your car was manufactured before 1996, an OBD I scanner is required.
If your car was manufactured 1996 or after, it requires an OBD II scanner.
Scanners/code readers can be purchased at any auto parts store for between $50 and $300. The professional type scanners/programmers used at dealerships and such cost several thousand dollars and generally require software modules as well for the particular brand of car in question.
You have a problem with the EGR system.
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Where is the diagnostic scanner port on a 1995 F-250 4x4
For just reading codes, any OBDII scanner.
Reading diagnostic codes is easy. The driver plugs the reader/scanner into the diagnostic port of the vehicle, and the scanner/reader will give a code if there is a problem, and tell them the type of problem.
As long as you can get the car to power up (the lights and accessories come on in the RUN/Battery position), you can plug in a diagnostic scanner in and retrieve fault codes. You do not need the engine running. If the car cannot power up, then the computer cannot turn on and the scanner cannot access the fault codes. In this case, you need to find out why the car isn't getting power before you can use the computer to diagnose any problems.
You need a scanner. Go to autozone/advanced auto and you can borrow a scanner from them.
Any OBD2 scanner will work.
Diagnostic plug. Diagnostic connector. Data link connector.
The auto service technicians probably have to buy their own OBD scanners, so it would be whatever they decide to buy in that instance. The Snap-On Solus Pro is probably pretty common. If you want to buy one, it's about $3900. For $150 - $400, you can buy a lower end model at various auto parts suppliers such as O'Reilly, Auto Zone, Advanced Auto Parts, etc.
The check engine light on a Buick Regal can be reset with a special diagnostic scanner. This can be performed at a car dealership or service garage.
Check the computer diagnostic codes. You can usually borrow, rent or buy a code scanner from most auto parts retailers.