On-Board Diagnostics "Not Ready"

[Violin]

Hey all -

My four year old lift-back failed emissions testing yesterday because the OBD was "not ready".

I had reset the computer by disconnecting the battery to clear a code related to my MAF. I think its related to my cold air intake and only throws a code on damp mornings if I accelerate hard too early.... but I digress.

I didn't realize that it takes a while for the computer to collect enough data for the emissions test. I've since driven about 80 miles in several trips.

Does anyone know if the "check engine" light goes through any sequence when you start the car to let you know the car is ready for testing (or if there is some other indication)?

Thanks for your help.

[CTScott]

There's nothing to indicate that it's ready.

I did the same thing a couple of years ago with one of my cars. There is a DTC that can be read for how long it's been since the computer was reset. I forget how many hours CT wants to see, but in my case I had cleared the MIL (for a flaky fuel level sender) about a week before going for emissions.

[BLH]

My Autoxray Scanner manual warns that using the Clear the trouble codes function will also reset the emissions readiness monitors. A complete drive cycle is needed before the vehicle is ready for an Emissions Test.

The emissions system has to be evaluated before the ready condition is reported.

http://www.txdps.state.tx.us/vi/Misc/faq/ready_not.htm#Changing

[Violin]

Thanks for your replies.

I drove it for two days, mixed driving totaling about 175 miles and the OBD were ready for testing.

Not sure if I could have gone much sooner or not.

[Jerkratt]

Hanging trouble with this monitor as well.. Any insite or have a procedure?

[tmontague]

Usually 200km of driving will do it. Drive on the highway for 20 mins between 100 and 120 km/h drive in the city for 20 to 30mins, make sure your car gets up to operating temps a few times and make sure it sits and cooks off a couple times (for EVAP test) you should be fine with the above.

Or purchase a code reader that show readiness checks and you'll know when you're ready