OBD II Readiness Codes | Ford Explorer Forums - Serious Explorations

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OBD II Readiness Codes


New Member
April 28, 2007
Reaction score
City, State
Bonney Lake, WA
Year, Model & Trim Level
'02 XLT
I took my '02 Ranger 2.3l in today for its emission check and was sent home. The technician said that I needed to complete a drive cycle so the monitors could run their diagnostics. The odd thing is that I have never erased any codes and have not disconnected the battery for several thousand miles.

According to my code reader the following monitors have not completed their diagnostics: O2, O2 Heater, Catalyst, Evaporative System.

The Misfire, Fuel system and Comprehensive Component are OK.

There are no trouble codes showing on my reader. I talked to the service dept at my local Ford Dealer. He had not heard of this problem and gave me the generic "...drive about 250 miles" (which I have read elsewhere in this group). I found more specifics on drive cycles at http://www.obdii.com/drivecycleford.html

Should I reset the monitors and start the drive cycle over? FYI-truck runs fine. I got 28 mpg from the last tank of gas.

I don't think that you need to reset anything; you just need to wait until the self-diagnostic tests have run.

Each system ( EVAP, Cataylst, etc.) have specific events which must occur before the self-diagnostic tests will run. That's why they want you to drive the truck to complete the tests.

Thanks, I will keep driving. In the past year I have started taking the train into Seattle, so my driving went from a couple thousand miles a month to a couple hundred. Maybe that has something to do with the incomplete diagnostics.