My daughter has a 2001 Nissan Altima and her service engine light just came on today. I took it to Auto Zone and they diagnosed this with the troubleshooting code of P0420
OEM Brand: OBDII Catalyst efficiency low-bank 1.
What causes this and how is this fixed. I would like some kind of idea before I take it to a dealership or somewhere else... you know being a woman they will try to screw me over and tell me there is more wrong with it than there really is...
Thanks
