error code reset procedure doesn't work

[rustfarmer]

I am trying to clear an error code for very small leak in evap system and the reset procedure followed carefully doesn't work. Unit never goes into diagnostic mode (ie: SES light never starts blinking). I tried disconnecting the battery negative overnight and that did not work either. Car runs fine. I replaced the gas cap and also replaced most of the rubber hoses related to the evap system so I want to see if the problem is fixed. Must I find a scan tool to reset the codes?

[VStar650CL]

A lot of Nissan ECM's from 2000 on don't have a manual diagnostic mode (and practically none of them after '07). So your QX may not have one. But even the cheapest $12 scanner off eBay or Amazon will read and clear basic OBD's on an '01 model.

[rustfarmer]

Thank you Vstar for your reply. I bought an expensive code scanner which would read real time data but the batteries failed and leaked ruining the wiring and main board. Guess I'll visit a pal who has a good scanner this afternoon since our local parts store can read codes but claim their scanner's won't erase them. Is it normal that disconnecting the battery overnight doesn't work?

[VStar650CL]

The ECM's after 2000 pretty much all store codes in EEPROM or flash and not RAM, so no amount of power failure will wipe them. So yes, that's normal.

[rustfarmer]

Thanks for that information Vstar. Most kind.

[rustfarmer]

Had a friend clear the codes with his Snap On scan tool. No further codes found and SES light is off. Fixed, but don't know if it was just a bad gas cap or one of the many hoses I replaced. But anyway, fixed.

[VStar650CL]

Keep an eye on it. Evap codes only get thrown while the vehicle is parked and only under specific conditions (1/4~3/4 tank, falling tank temperature), so it can take awhile for them to recur.