Knock and o2 sensor codes?

[DarkStar]

I was on my way home from work and the service engine light comes on. I have a 1997 240sx 5 spd. I do the self-diagnostic check and I get codes 33 and 34. Which is the Front o2 Sensor, and the Knock sensor. I'm curious as to what could have caused this. I wasn't driving it hard, and really haven't much. It was just a normal ride home, and as I was passing through an intersection, it came on. No noises, no nothing. Please get back to me as soon as possible so I can get this fixed. It doesn't seem to have caused any damage, no smoke or noises out of the ordinary. The little light is just annoying and I would like to get the problem worked out. Thanks in advance!!!

[DAEDALUS]

Neither of those items lasts forever. The car being 8-9 years old, they were bound to go out. The knock sensor may have been bad for a while. Replace them both--you will probably notice a good improvement in performance and gas mileage. Without them working, the car is running rich with retarded timing.

[DarkStar]

Yeah, I have been smelling a little fuel in the exhaust....Thanks alot!

[DAEDALUS]

If the car still runs rich after you replace the O2 then you may have a leaky injector. But I think that would be a different code.

[DarkStar]

Yeah, its only throwing those two. Thanks again for the help, its greatly appreciated!

[240sx2nr]

how much would a new knock sensor and o2 sensor cost? my 95 240 threw out the same codes when i hooked it up on a scan tool except it was b1s2 post cat o2...

[ILikeMy240sx]

A brand new knock sensor costs around 90 bucks shipped on ebay

[ddgsxr504]

You can pick up a Bosch O2 sensor from Autozone or equivelant for around $20-$25 bucks!

[ddgsxr504]

By the way nice Pic (ILikeMy240sx) Shift_Timing chain guides. That's one motto that all KA owners should live by.

[ILikeMy240sx]

[w1ngzer0]

Neither of those items lasts forever. The car being 8-9 years old, they were bound to go out. The knock sensor may have been bad for a while. Replace them both--you will probably notice a good improvement in performance and gas mileage. Without them working, the car is running rich with retarded timing.

Where is the knock sensor? is it just the o2? or are they 2 different things. I gotta learn somehow

My friends 240sx is throwing a 34 and i don't know the location of the knock sensor. Then later we ran it @ 2k rpm and turn it off then the ECU threw a 55....

[brisknfade]

Oh man that knock sensor is a ***** to get to. It took me literally 3 hours and a lot of swearing taking it off and putting in the new one without removing the intake manifold. Its bolted to the block by one bolt and under the intake runners. Its kinda hard to see, and even worse to try and take off.