I recently purchased a 2004 Nav and replaced the original battery with an Optima.
Locally I am required to have the vehicle tested for emissions and had them tell me it failed and needed to be driven before the "board" was ready.
Their tests consists of plugging into ADL plug and and gas cap.
I'm guessing their scanner is checking for certain codes that might fail the test.
I have not seen any check engine lights so far.
I also put a small cheap O'Riely's scanner on it and had no codes.
Question: When the battery is replaced or disconnected, does the vehicle have to go thru numerous drive cycles to reset itself, so to speak?
If so, how many or does it depend on the type of driving cycles?

Thanks

 

Yes, you have to drive it about 60 miles before the computer relearns everything.

 

The OBD-II (On Board Diagnostics - version II) System contains a series of programs called "Monitors" that check for various faults within the system. When the testing facility plugs into your ALDL they are checking the status of these 'monitors'.

If you disconnect power to the PCM or clear the check engine light the PCM automatically sets the status of these monitors to "Incomplete".

Three of these monitors are called 'continuous' monitors as they run continuously when the engine is running. They are the 1) Misfire Monitor, 2) Fuel Sytem Monitor, and 3) the Comprhensive Component Monitor. Their status will be set to "Complete" when they run.

There are up to 8 "Non-continuous" Monitors and they only run when specific condictions are satisfied. They are 1) Catalyst monitor, 2)Heated Caralyst monitor, 3) EVAP monitor, 4) Secondary Air monitor, 5) A/C Refrigerant monitor, 6) Oxygen Sensor monitor, 7) Oxygen Sensor Heater monitor, and 8) EGR System monitor.
Not all vehicles support all non-continuous monitor. If a monitor is not supported by a vehicle its status will be set to "Not Supported". If when the monitor executes, it finds a fault it will set the monior's status to "Incomplete" and store a DTC (Diagnostic Trouble Code). If it doesn't find a fault it will set the monitor's status to "Complete"

Depending on where, how, and the time of the year you drive, it can take up to a couple hundred miles of driving before the proper condictions are satisfied in order for some non-continuous monitors to execute.

IIRC, some States will pass a vehicle that has one supported monitor that is incomplete.

 

Guys,

Thanks very much for the details.
I now understand better what is happening with the monitors.

Great stuff here on FTE!!!