Incomplete Monitors Problem on my 2001 Ford Ranger 3.0 4x4, needs smog and monitors still read "incomplete" after completing the ranger drive cycle 4 times and putting in a good 500 miles. Changed the computer got it re flashed as instructed by mechanic as well as new cat along with all new oxygen sensors and heater sensor and still reads 02 sensor incomplete, 02HTR sensor incomplete and cat sensor incomplete. I really don't know what else there is out there to try. If theres any other way I can try to complete these monitors please help if not I will be forced to take it to dealership and spend the 3,500 they charge me. any help??? please and thanks.
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2001 Ford Ranger Question: Is there any other way to complete monitors? or what might be wrong?
Answer #1cardocIII from Gillespie's Auto Service, March 18, 2014, 19:47Master
Where is the 3500 number coming from?
When it comes to completing monitors the first trick is to look-up the codes that the monitor could generate and study the code enable criteria. That will give you the exact conditons that have to be met for a given test to run. Ford is very strict about it's routine, the O2 heaters must complete before the O2 sensors themselves are tested, and the Catalyst monitor doesn't run until after the fuel trim and O2 sensors have been tested. So, something is blocking the O2 heater monitors (tests) from running, and what ever it is will be spelled out in the code enable criteria.
There are lots of top techs who can handle this repair, and they don't all work at dealerships. One out of five cars that I work on are sent to me by other shops for just this kind of a problem.