diagnosis

You can do an instrument test, and step through any recorded fault codes from the OBD;

In message , Dreamerguy wrote

If the yellow warning light is on you can read the error codes. However this is not really a full diagnostic test as it only shows what may be faulty - even then some faults such as a coil pack failure may produce some erroneous codes.

If you have a problem it may be worth posting here with the symptoms.

The OBD connector must be in an easily accessible place within the car. On a UK 2001 Focus there is a small removable panel just above the shelf that is just below the steering wheel.

You need a OBDII (OBD 2) code reader to read the engine fault codes.

Links

Unfortunately this site is not a useful as it used to be - they were forced to remove some of the general information for legal/copyright reasons.

I have a cheap OBD II (OBD 2) reader similar to

Tiny URL (via the Tiny URL sponsor link)

The above just plugs into the OBD port. It then reports the error code 4 times. On the 5th read it also clears the engine light but you can disconnect it before then until you fix the fault indicated by the code. (Obviously, if you don't fix the fault the light will come on again)

Okay Thanks for the post.. Will look into that. Me myself I am just a "shade tree mechanic" I would rather sit in the shade than do mechanics.. But what I have here is an idle problem.. when you come to a stop sometimes abrupt sometimes regular it will act as if it is trying to stall out, also does it when I turn on the a/c. Only when you have it in park or neutral though. it doesn't seem to be tripping any codes though, but I figure a tune up probably wouldn't hurt it any though. if someone knows something else that might cause that I would definitely appreciate another post about that.. lol

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