Knock sensor still!


New Member
I have had code 34 since i bought it, seems to drive fine and runs about 9 PSI.
Have changed the knock sensor for a bosch one and Knock lite from Thor racing I also rewired it back to the ecu with a new plug, turn the ignition only on it shows 55 as soon as you start it and rev the engine (without even moving i.e no load) it shows 34 again. It is obviously picking some noise up but could it just be engine noise? if so how can I check?
With the new sensor fitted it is acting the same as before so I wired the old sensor in and did the same test with the old sensor wired up but sitting in the foot-well it didnt detect any knock.
Any ideas would be appreciated especially on how to measure what the sensor is detecting.


Active Member
As far as I remember, a code 34 is not representative of 'knock' being detected, just of an issue in the system itself.


New Member
Your problem lies with the type of DET sensor used.The one you swapped the OE item for is not designed as a replacement for thr GTiR its only for use with the KnockLink it comes with.You need a Nissan replacement to correct the issue and to re-locate the KnockLink sensor to another position.


New Member
I did originally think both of these points were correct but as the new sensor is acting exactly the same as the old one and it leads me to think that if the sensor detects too much 'noise' it throws up 34 (some people disagree).
Also I wired in the old sensor to the footwell and detacted no fault code but I then tapped it with a metal object and it showed up the fault so surely this shows if it detects noise its shows up 34?
Does anyone know how to test (possibly with a multi-meter?) for what should be detected by the sensor?

I will eventually get to the bottom of this annoying fault!


New Member
When I bought my car, it would throw up fault code 34 when I drove it hard.
I would reset the ecu and if I drove it like an old woman, it stayed clear.
A new nissan sensor fixed the problem.
Sorry, I do not know what the impedance should be or if it can be said good once measured.
Your sensor may be on it's last legs and acting over-sensitive as mine was.


New Member
Wiring the old sensor up and sticking it in the footwell will not be representative of having it in the OE location.

If you are able to fit a known good OE sensor and it still pulls up the 34 code then i would start to investigate the reasons behind why the engine would be producing knock.

Check the fuelling, timing, top of pistons to ensure no damage. Check plugs also to get an indication of whether the ignition system is working.

At least with checks its not costing you anything and if you are able to identify any problems in these areas, all is good and well.



New Member
if you used a hammer and got the fault then you know the sensor is faulty!!! it is sending out an obsure reading the ecu cant interprit and hence the fault code.

if you using a different sensor then you will get the same code as it still cant understand the reading its getting

put a new sensor on it


New Member
the bosch sensor is usually a resonance type which are used for eg on Honda's. These sensors work differently than the OE Nissan sensor. these react to knock with a leanear voltage. The NISSAN OE is more of an ON/OFF type.

Change sensor to OE.