P0420 NISSAN -

Question

My 2005 Nissan Frontier with 4.0 had a code U1000. I had cleaned and retighnted the battery terminals and the condition continued. Truck ran at 200 rpm, stumbling and non responsive to acclerator. When I brought it to the dealer, the code was erased due to me disconecting the battery. I had pulled into a Auto Zone when the truck was acting up and when they scanned it, it had the u1000 code.
Since there was no code at the dealer, I kept and drove it arround and the same system came up and and this time the light came back on and I drove it back to the dealer.
They pulled a code PO420 and want to replace a cataylitic converter.
Can running it in the u1000 cause the truck to misdiagnose and throw the PO420. U1000 is a ground issue with the ECM. I do not want to repair the wrong thing.

Answer 1

The u1000 will not cause the converter code. It is likely there is an issue with the converter. However, repairing the converter will not resolve the u1000 code either. This is a ground issue normally so you are right about that.