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I have a Nissan altima 96' and it doesn't pass emissions test says readiness monitors were not set : catalyst, oxygen sensor, EGR system. how do i fix these things
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when you change a component in emissions it changes and clears the ready back to inc so you would need the system to cycle through to get it into ready mode dont change any thing just need to put mileage on it or try a quick cycle https://www.smogtips.com/smog-question/2833/2001-Nissan-Altima-OBDII-Monitors-Not-Ready
Buy a cheap code reader and always scan your car BEFORE taking it in for inspection SO you never have to pay for a retest after failing again!
And just drive around town for about 15-20 minutes and use code reader to check readiness indicators again.
O2 Emission Monitors & Evap Monitor-- are two
different systems
Get ALL your OBD Codes & work them one at a time,
& DO NOT Clear any data with code reader or removing
battery cable, or the monitors ALL have to run again
The heater may work in the sensor, but the sensor doesn't
switch fast enough or is worn out & the front sensors get
replaced at 100,000, before they fail or slow down
The Evap Codes will be needed, to work on that issue
That monitor runs last & only every few days
IF--- you had professional scan tool software, you would see
11 monitors & maybe 8 that run on your vehicle
There will be at least 2 for the O2,one for cylinder misfire,
one for evap, one for egr,& three others
You have 8 I/M or Emission Monitors that have to run clear
BEFORE you can go to inspection
Your Catalyst Efficiency comes from the switching comparison
of the front & rear oxygen sensors being out of range
Until you resolve the rear O2 Sensor Heater Issue you won't
know if the cat is good or you have other problems
You need professional scan tool software & a long road test
to even find a problem,then component test,which apparently
wasn't done when they hung the new rear sensor on based on a code
could be a non operating oxygen sensor heating, check connector and damaged wiring, as it is posible to damage wiring or connector at this very hot plecement. Amclaussen.
Sandy, If you have an EGR Monitor that will not set then most likely there is something wrong with the EGR System. There are several things that can cause this depending on the vehicle and engine type. (1) Bad EGR Valve. (2) EGR Vacuum Solenoid. (3) EGR Vacuum Solenoid Wiring problem. (4) EGR Flow problem due to restriction from carbon build-up. These things must be addressed one by one and repaired before it will ever run that monitor. To answer your question you can GOOGLE your vehicle year, make and model and engine for monitor drive cycle and it will show you how it must be driven exactly. Hope this helps and have an awesome day Sandy.
The following conditions must occur to complete a Trip and test all OBD II monitors and components including the Catalyst Efficiency Monitor:
-- The misfire, comprehensive component, and adaptive fuel monitors are checked continuously from engine warm-up and can complete any time.
-- The exhaust gas recirculation (EGR) monitor test requires a series of idles and accelerations.
-- The heated oxygen sensor (HO2S) monitor requires a steady speed drive for approximately 1 minute at 30 to 40 mph.
-- The catalyst efficiency monitor requires a steady speed drive for 1 minute and 20 seconds beyond the HO2S monitor test at 40 to 65 mph.
If you cut engine off before test are completed then you must wait for a 6 hour cool down before monitors will run again.
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