OB2 Readiness Monitor
Can someone please answer my question? I replaced a crankshaft position sensor on my son's 99" Dakota 3.9l w/5 speed manual trans. The truck was running rough & barely would would idle, it showed a DTC of P1391. I had the battery disconnected for a few days before I installed the new CPS (got the wrong part the first time and had to wait till the weekend to finish the job). After the sensor was installed & the battery reconnected the truck started right up and ran great and the DTC went away. The trouble now is that when I hook my code reader up it shows one of the I/M readiness monitors (the O2 heater sensor) has not reset it's self to ready status. Immediately after test driving I noticed that three of four monitors reset within 15 minutes of city driving. It has been almost a month and we have driven more than 700 miles, 4 tanks of gas, and well over 60 cold starts. We have even tried following the "Chrysler Drive Cycle proceedure for O2 Sensor Heater Monitor Drive Trace" but still this monitor is not ready. Is this a problem or will the monitor just set to ready on its own after time?
Thanks in advance, Mike