drive cycle

[tr04]

hello all. newbie to the forum here looking for a little help. i have an 04 liberty 3.7l that i have a problem with. i reset my CEL (on for fuel level sensor but happens very interm.) and have driven it about 300 miles since. i connected my scan tool to check my Readiness Status today and my o2 sensor and catalyst havnt reset yet (still show "not ready"). i know that on most if not all vehicles the drive cycle will not begin if the vehicle has more than 3/4 and less than 1/4 tank so i usually drive with a half tank. is there any special drive cycle that needs to be done and how long does it need to be driven for them to show "ready". thanks for your help

joe

 

[SabaII]

o2 sensors and catalyst will not show ready until they have reached a proper operating temperature. A lot of times (that I have seen) the catalyst will not show ready or "light off" just idling. Drive the car and have someone monitor the scan tool. If they do not heat up in the allotted amount of time the ECM gives then they will throw a code.

 

[Doublecardan]

Joe, in order for the monitors to run they need to do it in specific conditions, those two you mentioned have not yet been run because those conditions have not been met, they may in fact be in conflict with other tests being run. The PCM task Manager determines the tests. If you want to run those tests yourself, have a look at the FSM on section 25 Emmissions, it will give you all the info you need to have those two functions set to ready.