1996 855t P0331 Code.

Post by **rguzz** » 03 Nov 2015, 18:19

220k miles and well maintained car with recent stage 0 tune and PCV stuff done by me, 02 sensors as well. There is currently an over boost problem which I am about to investigate, the well known usual suspects will be looked at first. Over boost has been present for a while but I drive to avoid bringing on the cut off. Anyway, most recently P0331 appeared though car seems to run fine. I have been using good (93 mostly) octane gas. In what way could my two problems (over boost and P0331 code be related?). My knock sensors have never been touched. Thanks, advise appreciated. Newly posting, long time appreciator of the site.

ferocity02 · Post by **ferocity02** » 03 Nov 2015, 18:39

I had the same code on my 98 S70. Over the span of a couple weeks I cleared it a few times and it would come back after a few drives, usually on the highway. I bought new Bosch knock sensors but before I got around to installing them the code went away on its own and hasn't come back. No idea what happened, bad gas maybe?

I would clear it and see if it comes back before you start throwing parts at it.

Post by **rguzz** » 03 Nov 2015, 19:04

Thanks. I just cleared it again (second time) and will drive on for a while. The sensors are expensive, and within last 6 mos did the PCV so not eager to go back in there. At least if I have to it will be familiar territory. I think there might be some correlation to the over boost issue...maybe.

Post by **abscate** » 04 Nov 2015, 05:44

I had knock sensor codes on my 1999 so replaced them when I did my PCV. I was told they don't go bad unless you cut the wires. I had a CVVT solenoid problem ( sticking) which probably caused the knock sensor code...I paid my used ones forward to someone who had damaged his and they worked fine

Post by **rguzz** » 04 Nov 2015, 12:58

I didn't know enough to pay attention to the knock sensors when I did the PCV, i.e. inspect wiring, consider replacing. Now, of course, I wish I would have taken a closer look. Is the consensus opinion that this code has nothing to do with my over boost issue?

Post by **abscate** » 05 Nov 2015, 09:33

I would agree with that. I would also not replace the knock sensors prophylactically. (Run that one through google translate a few times)

Post by **rguzz** » 05 Nov 2015, 15:16

Good. Thanks, I'm sure you are right. Now I don't feel (too) bad. Code has not come back after 2 days driving. Erased it a week ago and parked it. Fuel was low so filled with 93 Shell which I'll basically use from now on, or equivalent. So maybe we're okay.