2001 Pathfinder Exhaust Issues

[Cooter_76]

Hello Nissan Experts!

I'm trying to help a friend with her 2001 Pathfinder (4x4 V6) and thought I would look to you for some guidance.

The story: She recently took her vehicle in to get inspected and was told she needed new catalytic converters. She mentioned to me in passing that this is not the first time she's had to have the cats replaced. Replacing cats multiple times within 11 years sounded odd to me, so I did some poking-around online. Found this thread http://www.that dead forum/pathfinder/ ... rters.html which references an update that can be made to the ECM which changes the parameters by which the cats' performance is judged. Also found this thread another-nico-exclusive-p430-and-p420-codes-t495997.html which contains instructions for tricking the downstream O2 sensor.
We started with investigating whether the ECM needed to be updated. She took the vehicle in to the local Nissan dealership this morning where they told her the ECM is up to date and that both pre-cat tube assemblies (??) are cracked and that they would replace them to the tune of $2400. I spoke with the service guy over the phone. He suggested that the exhaust leak itself may be causing false readings from the O2 sensors. Either way, they'd have to be replaced. Looking online those assemblies are pricey ($850 ea.) When I told him this is not the first set of cats she's replaced, he suggested the dig further to find out if the fuel pump may be over-pressurizing the system, causing the engine to run rich and fouling the cats.

The questions: Is it worth bothering to try the spark plug non-fouler trick to clear the codes, or is she just going to have to bite the bullet and have the assemblies replaced. Are there any other cheap/easy fixes? Any clues as to why this issue occurs so frequently?

Thanks in advance!

[Towncivilian]

It's odd that this vehicle is going through cats so quickly. Is an excessive amount of oil being consumed? Typically, aftermarket cats may not last as long as the OEM parts - you mention the cats were replaced once already.

I'd run some fuel system cleaner containing PEA (which is proven to clean effectively without leaving behind its own deposits) such as Chevron Techron, Gumout Regane, or Redline SI-1 and change the fuel filter to see if that changes anything.

OEM cats can be purchased online for about $567 each before shipping, but this is still quite pricey indeed. There are cheaper options on RockAuto; if you end up ordering anything from here be sure to use a 5% discount code.

The ECM update you speak of is related to rear O2 sensor codes, not P0420/P0430 codes.

Welcome to NICO.

[towncarblue]

isnt the p0420 / p0430 the codes for the rear 02 sensors [ post catalytic converter? ]???

[Towncivilian]

isnt the p0420 / p0430 the codes for the rear 02 sensors [ post catalytic converter? ]???

P0420 / P0430 are cat codes. O2 sensor codes are in the P01xx range.