maxxWill

Hi all, first post here. Tried to do a search but said I don't have priviledge to that function !???

Anyway, after getting the codes to my check engine light (thanks Maxima.org!) I discovered the 3 things were wrong as I listed in the title.

I knew about the egr but the mechanic said it wouldn't impact the car in any way and was a lot of $$$ to fix.

Don't know what to think of the rear O2 sensor error.

The knock sensor really bothers me, I'll start tracking gas mileage but I honestly haven't noticed any loss of power!

twiggy144

O2 sensor most likely triggered knock sensor code. Fix the O2 sensor, reset ECU drive a littl while, anc check codes again.

maxxWill

So does that mean the knock sensor is helping the ECU with timing advance as normal?

Is fixing the O2 sensor expen$ive??

twiggy144

O2 sensor 50-75$ at www.buyoxygensensors.com
20-30 minutes to replace.

When knock sensor hears knocking, it retards timing to reduce knock and protect the engine. Valves and connecting rods suffer from knocking.

maxxWill

Thanks, twiggy144. I'm just wondering if the O2 sensor triggered the knock sensor code does that necessarily mean the knock sensor is not working?

I'll look for something in the stickies regarding replacement of the rear O2 sensor. Hopefully not too hard.

bruteMax

I had the same 3 codes come on at once a few months ago. As per the sticky on this forum, fixing the rear O2 sensor will eliminate the other 2 warnings as well.