Code52 - Knock Sensor

[Socks]

I fucking detest this fault. Seen in on 2 eps now and difficult to trace/track down and fix.

Right. Bought a GT few weeks ago. Had a broken knock sensor (was damaged when the headgasket was done) the connector and wire are in tact and seem fine tho.

EML is on as soon as the engine is started.

So I change the knock sensor. Connect everything back up. Clear the fault code.

Start the car. No EML anymore.

However whn revving the car to 3000rpm. The EML illuminates again throwing the same knock sensor fault code.

Now. Due to the fact it doesn't throw the code straight away. Means it recognises the fact the sensor is there. However. When revved either it is actually knocking.... Or there is a gremlin elsewhere.

Now I know the knock sensor is good. It came off another starlet turbo I was using ran perfect!

Checked the cambelt timing, distributor, fresh fuel. I don't think it could actually be knocking if I'm honest!

Any ideas chaps?

[5e colin]

trace it for a crack in the wire and tape it up really wel an not rubbing of anything

thats where i would start cant be anything else really

i got code 12 and 52 when i bought mine and the cable wasnt there and no sensor so i traced back the wire and instaled a thick shielded wire and taped it up well and have a spade connector pushed in the sensor it cleared both codes and hassent come back for almost 3 years now

[Socks]

How far back did you go Colin? Back to where loom enters the bay? Back to fuel tail? Back to ecu?

Sounds like an utter pain in the arse haha

[daniel_g]

Check for continuity / resistance between the sensor wiring and back up to the ECU. Checking at various points along the way.

The wire itself should have some sort of shield on it that gives it an earth.

[fiddlersport]

its shieldid all the way to the ecu

[Turbo Goose]

My knock sensor did the same past 3k rpm.

Unplug the knock sensor and unplug plug 2 i think on the ecu (check the pin out diagram for the pin to go on)

Grab a multimeter, set to ohms and get a mate to hold one probe on the knock sensor plug and you hold the other probe on the correct pin ( i had to pop a bit of wire into the pin as the multimeter probe was too fat) should show good continuity

Also check the screen by using multimeter.

Set to ohms, cut a tiny tiny bit of the screen insulation off near the knock sensor to get your meter probe on there or there might be some screen braiding on show near the sensor. Then put the other meter probe on the neg of the battery. Should be continuity.

Edited December 2, 2014 by Turbo Goose

[5e colin]

How far back did you go Colin? Back to where loom enters the bay? Back to fuel tail? Back to ecu?

Sounds like an utter pain in the arse haha

it is an pain ha ha i tapped in on where the injector 4 plug joins in the loom i soldered it together with a heatwap/shrink over it then taped the whole lenght of the cable to the knock sensor i used almost 2 rolls of black electro tape

[patman]

Mine was the same or should I say I noticed the knock sensor wire wasn't even in after a few months into buying mine, have located my wire now, as the engine was out and there it was sitting in the injector loom bit what goes across the back of the rocker cover, and the idiot before me took the EML bulb out!