Scooby-Scotty

CEL light flashed up this morning so i joined the to black wires up under
steering column and got code 22. Am i right in saying that's the knock sensor?
Where is it located and is it ok to drive till i can get another?

cheers scott

Splitpin

Code 22 does refer to the knock sensor, yes. The sensor itself is bolted to the back of the engine block just behind the number 4 cylinder. You will need a 12mm socket to undo the bolt which you should, just about, be able to get to with a 12" wobble extension. Access is normally easier if you take the intercooler off. If you look underneath the inlet manifold where the wiring for the coilpack and ISCV run you should see a round black plastic piece with a bolt through the top and a plug sticking at an angle out the side.

Beware though that sometimes on a 99/00 car the code 22 error can be triggered by a failing airflow meter. As such, if you have the option it'd be worth running some precautionary checks to ensure the AFM is okay, especially if it's more than a couple of years old.

Make sure you reset the ECU after fitting the new knock sensor. The car should be okay to drive off boost until it's sorted.

joey_turbo

iTrader: (26)

It's worth resetting the ECU before you change it too.
I had code 22 about two years ago. Ordered a new knock sensor from Subaru, but reset the ECU on the way, and the lights not come back on since.

Scooby-Scotty

thanks for the quick replies lads.

I've reset the ECU and it just comes straight back on.
what precautionary check do you recommend to check see if the MAF
is at fault?

cheers scott

Splitpin

If it's come back on that quick I'd be reasonably confident that the knock sensor *is* knackered and go ahead with a replacement.

Although if you want a bit of double endemnity and have access to a multimeter, you can test the sensor off the car. Check for the resistance across the two pins in the socket - you should see somewhere around 555K (min of about 530, max of 590). There should also be a dead short (i.e. zero ohms) between the right-hand pin in the connector and the steel part of the sensor body.

As above, in your shoes right now I'd just go ahead and replace the knock sensor, but seeing as you asked:

If you don't have access to anything that can actually monitor the ECU datastream, a wideband O2 gauge or engine noise (knock) monitor, about the only remaining practical way to check a MAF sensor, especially on a 99/00 is to put a new one in, reset your ECU and see if "the problem" (whatever it is) goes away.

That'll cost you best part of £100 to buy the new sensor but if it doesn't make any difference you can put the original back in and stick the new one on your shelf for the next time you need it.

Does your current MAF sensor have a stripe of green paint and a date code printed in white ink on its mounting flange, by the way?

The rookie

iTrader: (1)

I have just swapped the knock sensor on my 99MY for a genuine and then found I had a Valeo sensor in the garage that was identical! Yours for £20 delivered if you want it - PM me!

Mine had failed due to corrosion up around the outside of the metal 'core', its been flagging the fault occasionaly for a couple of years then over this winter it started to come on practically every journey so it was swapsy time!

Simon

172sport

iTrader: (6)

I have seen the same and it turned out to be the bolt loose..........

Scooby-Scotty

bugger i ordered one form subaru yesterday for £88. i must come on here more often lol

just checked and its deffo not a loose bolt but thanks for the suggestion