knock sensor - using on from a A3/tt/bora/golf/sharan???

[PeteG40]

in my box of bits i have one of these - plug is same as a g40 one (althought brown not black) and it looks same where it mounts on the block.

weirdly it has part number

06A905377A

g40 one is

030905377

very similar.

will it be useable - as all in all these are only little microphones?!?

[Alexiskayak_7]

If the sensor plug has the same numbers of pins and the plug can fit in the G40 loom they are the same...
Also, if the sensor has the same diameter with the g one... Then it's fine...

[Dan]

They are just a piezo electronic sender. Having such a similar part number you would assume they work the same too. Thats only a guess though 

[hayesey]

I guess the test is to plug it in, see how the engine runs (if the ecu is getting false knock sensor readings then it'll be retarding the ignition and would make the car feel lifeless).  Then plug a vagcom in and see if it shows a fault code for the knock sensor value. 

[Andy]

Just be aware that the part number being similar doesn't really mean much - they're similar because the parts perform the same function, i.e. they're knock sensors, doesn't make them compatable...

Having said that, there's not much to that style of knock sensor, they're pretty crude. Only issue I'd see is if the alternative part was setup to be more sensitive to a different range of knocking - the filtering of the signal is all done in the ECU though, so as long as it's physically the same size and shape the chances are it'll be fine.

All pretty irrelevant, as that kind of knock sensor doesn't really do all that much...

[Fred]

Test the connections with a multimeter Pete.
they should read somewhere near the same if compatible.
I had to replace one on my Fiat Marea 1.6 ltr estate after the
car develloped a sluggish running Fault.
A mate plugged in his Snapon scanner and that was the only fault
it came up with but after buying a new Knock sensor and pluggin in
the scanner again it came up with the MAP sensor wich was the fault.
There was nothing wrong with the knock sensor so that was a waste of
£80.12p
Having said that, it also looks exactly like the G40 one but i havn`t as
yet tested them both to see the difference but i will.
Back then i had the correct value in Ohms to test it but i can`t
remember what it was and yes they are essentually a microphone
simular to the cartridge on a record player.

Fred.