The Lambda Warning light is on intermittently and the fault code (using the magic diagnostic box) implies front knock sensor signal faulty.

I can't even see this sensor without removing the inlet manifold so I'm reluctant to start the job until I've got all the gen.

From what I can find out, the sensor is a piezo electric strain guage which effectively acts as a microphone to detect the shock wave if pinking occurs.

Is it likely that the sensor, connector is duff and if so, how easy is it to remove the inlet manifold?

Thanks in advance.

I can't answer your exact question but I do recall reading here
that the sensor must be tourqed very accuratly. If the tourqe
value is low (I don't know what it is) you might need a special
tourqe wrench since most won't be very accurate at either ends
of their range.

Some claim they can get to the front knock sensor without remove the intake manifold but I dont see how.. you have to be extremly flexiable hand to get under all the pipe...

Some said they can see the front knock sensor from under the car.. You may want to try it and see at least get idea where it seat and located..

I have replace and upgrade my knocksensor kit cost $75 and I replace it myself..

take me 6 month to get the courage to do it.. take me 2 day. but now look back I could have done it in 5 hours...

the knocksensor hold in place by only 1 bolt in the center of the sensor...

there are 2 sensor 1 for the front and 2 for the back...

many said you can just clean the connector and the problem will go away..


After I replace the new kit it good for 3 week the code 143 come back again and never go away.. so my replacement job was not solve any thing most people think it could be the ECU compute problem....

1. when you remove the intake manifold you need a new gasket
2. I do not need any new injector O-ring dealer said I can clean them up and put some vasiline on the Oring it work fine no leak..

3. But you need the body throatle gasket...

4.. Just mark all the hose line so you remenber what go where..

Yes I said you can do it... just get into it not that complicated as it look..

it was a great learning experience for me... I am very happy to take on the job


good luck let know how it turn out....

my english is poor hope it hepl you in some way....

Thanks for your help. I persevered and got to the sensor from the front of the engine using a mirror to see it initially. Luckily for me, the connector was corroded. A few insertions and a squirt of spray grease cured it.

Thank you for your wisdom.

Do you still get the fault code?

If so I wonder if your engine like mine, is transmitting a higher noise level which the ECU interprets as pinking? I'm guessing, not knowing what criteria the ECU uses to determine what a "faulty signal" actually is.

My T5 which I have recently bought has done 182000 miles.

I will attempt to gain access from the side to check the connector for starters.

If thats ok, I might try swapping the front and rear sensors if they are interchangeable.