Car troubles...again!

[Spivonious]

Different car this time though. My wife's Neon is still doing fine.

My car (2003 Focus ZX3 2-door hatch) refuses to pass the emissions test. Everytime they plug in to the OBD, it responds with "Not Ready". I've taken it through a few drive cycles and it still refuses to complete its tests. This latest trip to the shop resulted in the mechanic saying that the OBD claimed there were only 2 miles driven on the car since the last OBD reset. I had driven it 10 miles to get it to the shop (a Ford dealership).

A similar thing happened last year, but driving the car around for an hour (mix of highway and city) and coming back to the shop filled in all of the tests.

It sounds to me like the OBD is working fine but loses its memory when the car is turned off. I checked all of the wires and fuses and everything looked fine. Does the OBD have its own battery to save its memory when the car is off? The dealership wants to take the car in for diagnostic work, but I'm very hesitant to just give it to them and pay them $85/hour to poke around.

Do any of the car guys here have any ideas as to what could be causing this? Would it be worth it to get my own OBD scanning tool and see what's really going on?

Lastly, how much would replacing the OBD cost? The car is only worth $3400 trade-in according to the Kelly Bluebook.

[Spivonious]

No ideas? I found a way to enter into a testing mode which tells me if there are any problem codes and there are none, so there's no "check engine" problem holding back the tests.

[CharvelRocker]

I think Fords have had some issues with the OBD systems. Our Taurus's check engine light would also get stuck on and just would not be reset. Went on like that for nearly 6 years until we finally sold it to a junker due to the car not passing emissions and needing new tires. Our mechanic said it sounded to him like the OBD had a short or something had failed in it. That said ours was much older, a '96.

[Razor]

If the Ford system works the same as a Nissan, then it may sets codes as "key cycles". I know Snap-On codes will be history (past) and on demand (right now). Key cycles basically means error codes set according to how many key cycles (physical turning of ignition key) ago that the error occured.

I also know that Nissan has a set way of checking emissions electrically with our scan tool, and it involves approximately five miles of driving at different speeds (highway and city) with several stops in between over a certain period of time/conditions. If I understood one of my techs right last week, most EVAP system codes on Nissans will not set at speeds under 30 or 35mph.

One other thought, to perform EVAP tests on Nissans the vehicle needs to be at cold temperature, and it takes a long damn time for vehicles to cool down. My advice would let them keep the car overnight and see if temperature is affecting the scan tool "NOT READY".

Only idea I can think of.