P1000

P1000 indicates that one or more OBD-II readiness monitors have not completed since the last code clear or battery disconnect — the ECU has not yet seen the specific drive conditions needed to self-test the catalyst, EVAP, EGR, O2 sensor, and heater monitors. This is not a fault code in the traditional sense; it is a status flag that almost always appears on freshly cleared modules or on vehicles whose battery was recently replaced, and it causes guaranteed state-inspection failures because most states require six of seven monitors complete (or seven of eight on pre-1996 OBD-II-equivalent). The cheapest-first ladder is: confirm with a scan tool that all monitors read INC (incomplete) rather than NOT SUPPORTED, then run the Ford drive cycle — cold start below 50F coolant, idle two minutes with A/C and rear defrost on, accelerate to 55 mph at half throttle, cruise three minutes, decelerate to 20 mph without braking, accelerate to 60 mph, cruise five minutes, then coast-down to a stop. Check monitor status; if EVAP refuses to set, verify fuel level is between 15 percent and 85 percent and ambient temp is 40F to 100F. The expensive misdiagnosis here is replacing parts to chase P1000 — there is nothing broken; a shop that quotes you a catalytic converter or O2 sensor based solely on P1000 is reading the ticket wrong.

Vehicle-specific patterns: 2003-2010 Ford Crown Victoria/Mercury Grand Marquis Police Interceptors notoriously refuse to set the EVAP monitor without the precise 15-85 percent fuel level window — fleet techs keep them at half tank during drive cycles. 2005-2014 Ford Mustang 4.6L/5.0L vehicles with aftermarket tunes (SCT, Bama) will clear codes on every tune flash and require a full drive cycle before emissions testing — schedule the tune at least a week before inspection. 2011-2019 Ford Explorer 3.5L vehicles with weak batteries lose KAM (Keep Alive Memory) overnight and reset monitors; load-test the battery before chasing a phantom P1000. 2008-2012 Ford Escape 2.5L/3.0L often fails the catalyst monitor in cold climates because the drive cycle requires sustained closed-loop operation above 40F coolant — drive cycles attempted below freezing rarely complete the cat monitor. Estimated repair: $0 to $150 (drive cycle only; $150 if a weak battery needs replacement to hold KAM).