USA car, doing USA smog, not told.
no engine told/
NO DTC errors told if see them now is the time to fess up or fail we will !
so taking the car to a real shop is out of the question/ IDK????
first off to fix modern cars we need a working scan tool (real not $13code reader junk)
you failed to say what (which) monitors fail or STALL why skip a key fact this?
the CMM is list of key smog tests that run all the time to be sure they all pass muster.
the list of CMM varies by year, country ,engine in the car. gas ?or diesel and engine size and most important engine real name and ID
the VIN #8 digit on USA car VIN is the engine code that matters
the smog system must clean up that engine only. SEE?
each CMM listed item has its own rules for testing it.
the SERVICE manual covers each one to the extreme.
but not told you which line item CMM fails?
but I do know the laggards ones, sure do
EGR if present (VIN engine coded)
CAT monitor, ( p042x errors mean it fail;s)_
EVAP is the tricky one.
some eVAP monitors flat refuse to run on any full tank if fuel or close to empty.
the SM is clear on that, if you read it.
MISFIRE monitor, no P03xx errors allowed, or by other coded DTC names.
Fuel System Monitor !
there most not be DTC ERRORS NOR CEL LAMP GLOWING RUNNING.
02 SENSOR ERRORS. NOT ALLOWED.
NOW MY ANSWER VASTLY MORE SIMPLE. IF CAR IS RUNING GREAT.
NO CEL, NO DTC ERRORS WHY MONITORS DO NOT CLEAR.
well gas tank full is one
or some errors stored are not cleared for 30 cold driving cycles.
the scan tool reset clears them all but then all the CMM monitors must time out and pass muster.
this how post is just wasted
no CMM line item was told at all
all codes to clear but this one, ( why skip telling what THIS ONE MEANS)
????????????
you must have a real scan tool. do you,? NOT TOLD YET.
MUST
to do your own work takes the tool.
or buy the service manual
read the page for error not told yet and the rules of each test are clearly stated
tricky examples (deep programming in PCM)
I had a 1996 car (sold) and the cat monitor would not ever complete!! stalled.!
but i scanned it, and behold the front 02 sensor was flakey
the PCM saw that and knew it and blocked the p042x tests for CAT monitor
it did that because that test will lie to you. saving $100 dollars wasted.
also learn this oddity
my silly mazda car, the EVAP test (test B) only runs at car parked and off
and fully cold and tank not full. EVEN as I slept it ran THIS TEST.
we'd hear the EVAP solenoids clicking at night. (LIKE A GREMLIN)
the SM told why. if read.(service manual)
THIS IS JUST ONE TOOL, (OBD2) ON ONE CAR,
NOT SAYING YOUR LIST IS SAME OR LONGER.
NOT HOW SMART MY TOOL IS (NOT SUPPORTED)
EACH MONITOR TESTS HAVE THERE OWN RULES,
THE SM COVERS EACH ONE IN DETAILS.
WHEN IT RUNS AND HOW IS TOLD
LOGIC RULES. (ENGINE SPEED AND LOAD, AND MPH OR EVEN COASTING FAST RULE) AND EVEN TANK TOO FULL. IT IS STALLED AT EVAP
THERE NEED TO BE AIR ON TO OF TANK TO RUN EVAP OR IT STALLS.
WHICH ONES FAIL FOR YOUR NOT TOLD HERE IS MY LIST. GENERIC.
EVEN A BAD TRANSMISSION SLIPPING.
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