Drive cycle criteria is probably not being met it maybe driving habits or a bad sensor or even a bad thermostat all these could factor in plus a few other factors needs to be looked at by a competent mechanic
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Customer has 1996 f250 California Obd2 cert truck. Has rear 02 sensor. Will not set any monitors after 3 weeks of driving.
She is looking for a shop in Sacramento area to check it out.
You might post this on Mr. Nate's Facebook page. There are techs from Sacramento that probably would be willing to look at the truck.
Just for the heck of it, have the customer drive it for a few miles. Have them go back to your shop, and check the monitors without shutting it off. If a monitor has run, and clears after shut down, you might not be getting power to pin 55 at the ECM.
Why make it simple, when it will work equally as well complicated.