Emission Monitors
Asked by tdtony3 Dec 30, 2019 at 05:30 PM about the 1999 Ford Expedition 4 Dr Eddie Bauer 4WD SUV
Question type: Maintenance & Repair
Hi all, does anyone know how long it takes for the emission monitors to reset themselves? I disconnected battery to do some engine work, went to emissions testing the next day, no codes but 4 monitors are still incomplete after 5 days, catalyst, evap system, oxygen sens mon, oxygen sens htr.
Thanks, Any info would help.
4 Answers
Since your vehicle is a 1999 model it will pass emissions inspection, under Federal Law, with two readiness monitors not set. Doesn't matter what two aren't set as long as the rest of them are set. To get the readiness monitors to set your gas gauge must be between one quarter and three quarters full. No more and no less! Drive normally for a few days with the gas gauge in that range and the readiness monitors will set. Off the top of my head I know the catalyst and EVAP monitors will not set if your gas gauge is above three quarters or below one quarter. Hope that helps! Jim
Thank you GA & Js08016 for your answers, Are these answers pretty much for ford or for all vehicles? Thanks Tony
You're welcome. Glad to help! For domestic OBD II (1996 and newer) models. Jim
Hi Tony again, I got a code p0171, checked for obvious vacuum leaks, changed pcv valve, changed fuel filter, 02 sensors checked out, hooked up scanner, stftrm1 & 2 bounce between -0.2 & 4.0, LTFTRM1 is 7.1 & steady LTFTRM2 is15.1 steady. I bought a new MAF sensor now my STFTRM1 & 2 bounce around -0.8 & 2.3, but now my LTFTRM1 is -10 & LTFTRM2 is -20 Does this sound right? Or could the pcm still be adjusting? Please help??
