1998 V70XC P0330 (Knock Sensor)

bubbeck · Post by **bubbeck** » 08 May 2019, 13:41

Hey folks!

Just the other day I noticed some hesitation in acceleration in my 98 V70XC, and shortly after got a CEL and a P0330 code (knock sensor bank 2). From what I've read here, this is most likely a problem with the sensor or sensor wiring, not an actual knock correct? For reference, I'm running 87 octane (which is actually mid grade here in Colorado - another side question I have is can you get away with lower octanes in turbo cars at higher elevations? That's why the gas grades are lower here...)

I'm not super jazzed on taking off the intake manifold yet again, so was going to check/clean the connector - does anyone have a picture of where the knock sensor connector is? Also, are there any tests I can do before replacing the knock sensor? E.g. resistances between pins on the connector?

Thanks!

tardcart · Post by **tardcart** » 08 May 2019, 15:23

87 will definitely trigger the knock sensor hard acceleration. but it should just retard the timing and not set a code. I am not sure if repeated signals sets a code or if the computer cant find the right resistance meaning bad sensor/connection. I think you can get under there to replace w/o removing the manifold. same as if you are doing the starter, tight and a mirror. now which is bank 2?

bubbeck · Post by **bubbeck** » 08 May 2019, 16:08

Really? I've been running 87 for years without a problem, and its the minimum grade recommended in the manual. Also, shouldn't the elevation (5400' here in Boulder) and lower ambient air pressure compensate for lower octanes in terms of predetonation? At least it does in NA cars...

tardcart · Post by **tardcart** » 08 May 2019, 17:23

I would guess 87 would be 89 at 5000 feet. still shy of 93. You would only have knock full throttle.
but since power is down 15% you would need full throttle to pass. especially with people going 90
in the snow like Ive seen and enjoyed. dry snow is a pleasure to drive on mixed with some gravel, but hell on the windshield.

Post by **abscate** » 08 May 2019, 20:59

They knock sensors almost never go. If the wiring isn’t damaged , I would look elsewhere.

They are not cheap.

Post by **precopster** » 08 May 2019, 23:19

If the knock sensor bolt loosens, (12mm bolt) the code can fire. There are 2 of them and they are tucked up there right out of the way.

tardcart · Post by **tardcart** » 09 May 2019, 04:23

side note, I replaced my metal to metal pass. engine mount and felt like the car was faster. It may have been setting off the knock sensor. the top of you engine should be flat not sloped to the pass side. very easy and cheap repair.

Post by **abscate** » 09 May 2019, 07:30

The torque setting on the sensors is low, so don’t crank them down even with your full arm

20 Nm which is a light twist with elbow strength only, or a torque wrench , even better.

bubbeck · Post by **bubbeck** » 15 May 2019, 09:31

Any hints on which wires go the the knock sensor/ do you think I can diagnose/fix it without taking off the intake manifold? Is the circled connector in this photo the one for the knock sensor?

bubbeck · Post by **bubbeck** » 15 May 2019, 09:44

Think I found my answer actually, with some instructions on testing the sensor. Looks like that is the connector!

https://www.pelicanparts.com/techarticl ... cement.htm

I guess my other question is, a lot folks seem to says these codes are generally not from bad sensors. What do they tend to come from? I guess I should also mention I've had P0440 code that I've been ignoring for years (its not the gas cap). Could they be related?