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Smog help!


Well-Known Member
I'm the original ones of a 2002 F150 5.4L 4wd that is having a smog issue. We can't check the smog, since it has a code stating the cat hasn't run. I've tried resetting the computer based on OBD 2 and via unhooking the battery, etc.

Does anyone know how to trigger the cat sequence? Is there a fix you've heard about? I'm stuck with a truck that can't be registered, but runs great.

Does anyone here have any history with working with the smog referee?

Thanks for the help.

(I'm in San Diego and will take it anywhere close if you guys know anyone who can help with this)

Slippery P

Well-Known Member
Catalyst 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.

Note: If he PCM tries to run the Cat monitor but experiences an out of range variance between the front and rear O2 sensors for any reason ( degraded o2s, exhaust leak, or degraded Cat) the test will be aborted and tried at another time. It will continue to do this until all parameters are met to successfully run the monitor.

Sometimes the cat monitor can be a real pain in the azz to run.
The cats can be degraded to the point the monitor will not run and the vehicle will run just fine.
If you know anyone with a scanner it is very easy to check, monitor the front and rear O2s for both banks, the front should cycle from high to low voltage, the rear should run at a steady "mid" voltage range. If the rear are cycling the same as the fronts your cats are toast.
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Straw Man
I'm not saying that Jason P is wrong, but to add a little more to what he said, if you can borrow a high-quality scanner, and keep it plugged in while you are driving, there is an indicator that will let you know when it is ready to be tested. Also, Google "drive sequence for resetting catalytic converter" related to your year make model.
What Jason said sound close, but sometimes it's a very specific set to follow, like accelerating from 10-50 mph steadily, 5 times in a row, then sustaining 55 for 10 minutes.

Good luck Matt

Sent from hyperspace

Slippery P

Well-Known Member
The drive cycle I posted is actually cut and paste right from fords workshop manual, I will add, I worked for Ford, Lincoln, Mercury for 5 years specifically doing drivability work, then moved on to work for Volvo for 8 years doing the same. If you cannot get it resolved and feel like driving to valley Center sometime next week, let me know and I can take a look at it for you.