I had the troublesome P0171 and P0174 codes on my 98 Explorer Sport 4.0 OHV. After changing gaskets, o-rings, IAC, PCV, oil cap, fuel filter, air filter, and cleaning the MAF sensor the codes seem to have gone away. (After all the trouble I believe the problem was the $5.00 oil filler cap).
I've been driving 2 weeks now and the catalyst monitor test has still not cleared. From the OBDII site I get...
7. Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from 40 to 72 Km/h (25 to 45 MPH) over a 10 minute period.
Executes the Catalyst Monitor.
Does this mean 10 minutes at EACH of the 5 speeds or all 5 within a 10 minute period? Would like 2 minutes (or 10 minutes) each at 25, 30, 35, 40 and 45 mph do it?
I average about 90 miles a day Monday thru Friday. I have put close to 1,000 miles on the car since I reset the computer with the scanner. My driving ranges from high speed freeway (~80 MPH steady) to very stop and go (I cross the US-Mexican border every day). I think I've gone thru the above procedure several times at least.
Any clues why the test isn't clearing? The C on my Equus Innova 3100E OBD II coder reader continues to flash. My registration extension has expired and I need to get the emissions certified.
Last edited by canyonbreeze; 11-03-2004 at 06:24 PM.
When you scan it now do you get a P1000 code or?
You've driven far enough now that the monitor should have completed. I wonder if you have a bad HO2S (O2 sensor that monitors the cat)?
The Ford manual says this for the Catalyst Monitor Drive Cycle.......
Make sure that the inlet air temperature (or ambient air temperature) is above -18°C (0°F).
Start the engine and drive the vehicle for 25 minutes.
Drive in stop-and-go traffic for 20 minutes, include six different constant speeds between 40 and 72 km/h (25 and 45 mph).
Drive on expressway or highway for an additional 5 minutes.
I don't get any codes. I don't think the scanner will read a P1000 as I have never seen that. It has little indicators that flash if the test has not completed. When I did a reset there were 5 of them flashing. All have stopped now except for the C which is Catalyst. Wouldn't a bad O2 sensor flag an error code?
I drive about 3 hours of stop and go and expressway every day. Last night the bad traffic was about 2 hours of between 5 and 45 mph. Then 30 minutes of 75 mph this morning.
Anytime there is a monitor that isn't complete it sets a P1000 code on memory.
A bad O2 should set a code but sometimes things don't always work how they should.
Are you able to read live data on your scanner to see if the O2s are all working?
For some more info on drive cycles etc take a look at www.OBDII.com
I'm not familiar with your scanner but if you do a KOEO and a Memory test there should be a P1000 if the monitors aren't complete. I think that either they are all complete or your scanner doesn't work how it should.
As an experiment you can remove a battery terminal for a few minutes and then scan it. A P1000 should always be there after doing that.
Following is a posted response from 'Test' at the www.obdii.com discussion board. I took it for a smog test this morning and it passed even though the Catalyst drive cycle wasn't complete. Many thanks to him or her for this info. The car has never shown a P1000 code, I don't know why.
Here is a drive trace and some preconditioning requirements for Ford catalyst systems.
MIL must be off
Time sequence start up 330 seconds
ECT between 170 and 230F
Engine load between 10 and 35%
EGR flow between 1 & 12%
Time since closed loop 30 seconds
IAT between 20 and 180F
MAF between 1.0 and 5.0 lb/min
Fuel level between 15 & 85%
Use your scan tool to check the preconditioning requirements.
They suggest a 12 minute drive
Drive for 6 minutes at a steady speed between 25 and 45 mph.
Use a different speed steadily between 25 and 45 mph for the next six minutes
Of course there may also be some other mechanical problem that is preventing the monitor from completing that was not enough to throw a code. Like an O2 sensor that is a bit on the "slow" side.
Also, if you only have one monitor not set on a model year 1998 vehicle it should not keep you from passing your inspection. The federal rules state you can have 2 monitors not completed at the time of inspection for model years 1996-2000. I've heard of some exceptions to that rule if you had failed a test for some codes and then come back to be tested again. They may require that any monitors that seem to be related to some trouble codes be ready when the follow up test is given. You might want to check on that before you make any valiant attempts to get the cat monitor set.
There is an MIL (Maintainance/Inspection Light) readiness test. If the computer has just been reset it will not pass. That is the only reason it failed the first time. I had just reset the computer the day before because it kept popping up with the P0171 & P0174 every day or two. The emissions and equipment all passed the first time only the not ready was the problem.
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