Hey guys, simple question for you. Sorry if it's a really daft question, but I had a check engine light on thismorning and I plugged the laptop in and the fault recorded was the knock sensor. So does the check engine light coming on for the knock sensor mean there was knock detected? Or does it mean the actual knock sensor is faulty?

 

Hi mate, i had this exact same problem with my knock sensor. took it to subaru to be plugged in and fault came up as knock sensor. The problem could be either of them. But i changed my knock sensor and all seems good now, problem solved. sorry it aint much help mate.

 

I have this problem right now
I am sourcing another sensor and hopefully that will do the trick

 

i had the same problem last month i changed it and was all good fiddley to do tho

 

Try an ECU reset before you change it. I had knock sensor (code 22 if I remember correctly) issue, done an ECU reset, and it never came back, over 3 years ago.

 

and if ecu reset doesnt solve it, change it. not too bad to get at, wiggly socket & extension can get you onto it once the intercooler is removed. but just a bit fiddly!

id the same problem & changed mine, all good since. when refitting new one, try to get a washer the same size as the metal collar on top of the sensor so that when torquing up the bolt it rests on the washer and not the plastic which can cause it to crack again

the plastic cracks overtime and lets moisture in which gives the intermittent error.

correct torque for bolt is 23nm DO NOT OVERTIGHTEN

 

Thanks for all your responses guys Yeah the problem is intermittent - the check engine light just seems to randomly come on for a few seconds while I'm driving and then goes off again straight away. Thismorning it was coming on then going off.....then on again....then off....not in any sequence tho, it was just really random.....and that was all while I was idling before I'd driven anywhere! I thought surely it shouldn't be knocking then. Anyway, I'll keep an eye on it, I just don't wanna damage the engine obviously, cuz I know how catastrophic knock can be!

 

Somewhat annoyingly, there do seem to be a few cases where a faulty MAF sensor can cause the code 22 error. I don't know why this should happen but trustworthy, reliable people have reported it. Therefore, the fact that you are getting 22 adds to the suspicion. Although the first thing you should do in these circumstances is to check or replace the knock sensor.

You *can* check the knock sensor with a multimeter. Set it to resistance mode and see what you get across its two pins. The correct number should be 555Kohm +/- 5% or so. There should also be a direct connection (i.e. zero ohms) between the right hand pin as you look into the plug with the sensor upright, and the metal part of the sensor body. Be aware though that even if this sensor passes a static resistance test on a multimeter, it's still possible (albeit remotely) for it to be damaged. If you see any cracking in the plastic body, in particular, precautionary replacement is advisable.

 

Hi guys, reviving an old thread here as I have finally got around to replacing my knock sensor because of having an intermittent & flickering check engine light coming on.....which was showing up on my laptop as Fault 22 knock sensor. Anyway, have replaced the knock sensor and now I have a constant check engine light that's on allllll the time. Doh! Here are my new & old knock sensors together......





My new one, even tho it has an identical part number (22060AA070), has got a yellow dot on it - see first picture. Does this mean anything? I know that there's a thing with a green stripe or dot meaning something on a MAF sensor? I was wondering does this yellow dot mean it's not compatible with my car for some reason? I just don't see how I can have fitted it wrong or why the light would now be on? Unless of course it's a dodgy sensor, it's possible I spoze. I have done an ecu reset and that hasn't got rid of it. Any ideas guys? I have a remap booked on 18th Nov so need to get it sorted before then.

Thanks in advance for your help

 

Started the car to come home from work tonight and there was no check engine light! I thought waheyyy it's solved......but then it came on about half way home and stayed on for the rest of the journey. Doh! I didn't use a torque wrench to fit the sensor, so would it throw up a constant check engine light if it was done up too tight/not tight enough?

 

Did you reset the ecu after fitting?, as the ecu will still keep it on "limp home mode"untill reset for the new sensor to start working.

 

That old sensor looks badly corroded, have you cleaned the mating surface?

 

I did reset the ECU yeah. I have only done that once tho, not tried it for a second time yet. That didn't clear the check engine light tho

I did clean the mating surface yeah, as best I could in the fiddly gap! It's just the torque I'm worrying about now cuz we didn't use a torque wrench. My mate did the bolt up and he did it pretty tight I think, so I wonder if that's causing it? Does the doing up too tightly mean permanent damage to the sensor, or just that it won't be able to work properly?

 

take it off and get it torqued up correctly and cross your fingers you havent cracked it by overtightening it

 

Hi Gambit. Thanks for this info, but I have just read on another website (subaru-impreza.org) that the correct torque is 24Nm? Ooh the joys of miss-leading information on the internet! How important is the torque? I don't really know if 1Nm is significant or not? Also, on the same website I've read that the "extraction area of the knock sensor cord must be positioned at a 60 degree angle relative to the engine rear"??? Has anyone ever heard of that before? I wouldn't have thought the mounting angle of a circular sensor would make a blind bit of difference?!

 

1nm is definitely insignificant id say I torque bolts for a living

 

Cool, I guess you know what you're torque-ing about then

 

Hi guys, just another quick question - does anybody know if there's a way I can test whether a knock sensor is actually working or not? Cuz it's obviously very annoying for me having to take my intercooler off (which I know is normally straight forward, but I've now got the much bigger STI8 intercooler on mine, it's a NIGHTMARE!!).....then fit a knock sensor.......then put the intercooler all back in nice.......then start the car to be greeted with a check engine light and an error code! Doh! Is the easiest way probably just to start the car with the knock sensor fitted before I put the intercooler back on etc? Just to see if the check engine light comes on?

 

It wont run without the intercooler

edit: Unless your mafless...

 

Really?? It won't just start and idle briefly? Only long enough for me to see if check engine light is on or not? I'm not MAFless no, what a pain in the ****!

 

By removing the IC your creating the worlds biggest air leak which the MAF wont know about or be able to do anything to compensate for

Get the codes erased and get the ECU read/logged to see what is actually causing the light to come on.

 

I had a similar problem (as you will see my earlier post) and the sensor was changed and reset. A day later the cel came back on and when I checked it, it was coming up with a maf fault.

Have you checked what the code is this time?

Just a thought

 

Yes it's definitely 110% the knock sensor bringing the light on I've done 2 ECU resets now and then next time I've started the car the light has come on again.......hook the laptop up and it's error 22 knock sensor every time. I'm gonna have a go at this now tomorrow anyway with my mate's torque wrench so I'll update then. I don't hold out much hope tho, cuz I'm really not convinced that the tightness of a bolt on a sensor could either make it work or not work? I have no idea! I could understand if I've tightened it up too much I might've actually broken it (DOH) but I can't see that loosening the bolt off to the right torque is gonna make it suddenly work. Ah well, only one way to find out isn't there!

 

I just thought......nobody's said anything about the yellow dot question? If you look at one of the pics above you'll see that my new knock sensor has got a yellow dot marked on it and my original one didn't? Does this mean anything? Just don't wanna go through the effort of trying to sort this one and then someone say oh yeay by the way, the sensor with the yellow dot won't work on a MY00 car

 

The pic with the 2 up the other way (so you can see the botom) looks to me like there 2 different sensors. Whether that's just me and my 4 eyes I don't know

 

Right, update time. First of all I got my mate's torque wrench, got in there and re-fitted the bolt.....this time with the correct torque of 23Nm.....



On my way to doing this tho, I pulled at the knock sensor cable to move it out of the way and the wire just slipped out of the end of the plug as if it wasn't even connected......



So I thought that must've been the problem surely.......bad or no connection. So I chopped the plug apart a bit so I could secure the wire back on.....



The clamped it in with pliers and soldered it also for good measure.....



Then waterproofed it......



Tidy! Plugged it all back in tho, did an ECU reset, and it's made f*** all difference!......



I think I give up! I've done another ECU reset aswell just to make sure. Still the check engine light comes back on, and it's defo 110% the knock sensor. It must be a dodgy sensor surely. Gonna try sealing up the top of my old one and putting that back in to see if it's any better. Doh

 

ive read a few instances where the knock sensor cel code is logged on the ecu but its turned out to be a faulty maf,
suggest you have a search on here on knock sensor and also code 22 and read through the threads to see if you can find them.
ill have a look too now

 

read this one
https://www.scoobynet.com/general-te...ault-code.html

 

So if that is true then when mine read as a faulty knock it could of been the maf as it now says maf sensor when the light comes on
But mine don't do it all the time, only on a long run.

 

Thanks Gambit, I have read this thread and it sounds like they were having exactly the same symptoms as me before I tried to change my knock sensor. With them tho, they had an intermittent check engine light before.....then changed the knock sensor and still had an intermittent check engine light......so the sensor change made no difference......which would suggest the problem lied elsewhere, and it did turn out to be elsewhere - the wiring of the engine loom or something. With me tho, my sensor change has made a difference - I had an intermittent check engine light before, and now after changing to a new knock sensor I've got a constant check engine light. Like straight away from startup, as if the sensor isn't plugged in at all. So that would suggest the problem is the sensor? I reckon the next thing I need to do is put my old sensor back on and see if I can get rid of my constant check engine light back to an intermittent one, cuz then at least that tells me my new sensor is a duff one. I think?!