After much taring apart and various testing I can happily report the knocking/thumping is NOT directly CVT transmission related but is in fact quite a common occurrence with Nissan's CVT equipped vehicles - the ABS / VDC module found on Nissan & Luxury American Infiniti CVT equipped cars now all feature a vehicle self test which will occur ANY time the car is stopped and restarted regardless of COLD or HOT operating temperatures.

The ABS and VDC self test (according to official Nissan literature) may (in this case DOES) emit an operational noise from any drive gear (forward or reverse) and during the first few moments of low vehicle speed (which of course in our cases here is around the 30KPH mark). The noise apparently is deemed "Normal" by Nissan and does not suggest that the module(s) are faulty and/or a cause for concern.

With this info in hand I took it upon myself to investigate the ABS / VDC module further today and after disabling the module completely I myself can verify that there is no further knocking/thumping noise that I'm sure those affected are familiar with.

I should however point out that although this resolves the annoying knocking sound, it is NOT a permanent solution as of course the Maxima has no anti-lock braking or traction control. After the module is disabled an array of warnings and fault lights remain lit on the dash, there is also no speedometer reading when the module is disabled.

So for those concerned with the knocking/thumping sound from their J32 Maxima's, Nissan deems the sound as a normal operating noise which of course is annoying to those who pay attention to it however I can't remember the test drive Maxima I took out ever having this issue but then again, it was already warmed up and driven before I took it out.

I might invest some time over the next few weeks in physically removing the ABS module from the firewall and inspecting the brackets that its mounted on because another situation may be in regards to engine noises, a knock or vibration from the engine bay can easily transfer through metals and "amplify" it elsewhere so it might need a bit of dampening from the firewall maybe.

Anyway apologies for the longish post but it is a sort of resolve for an issue brought up by a couple of us already, if anyone is interested in trying out the ABS disable themselves I'll write up and photo the steps but fair warning, disabling any safety device on the car deems it defective and insurance wont cover any damages caused. But if your not content on taking my word for it then the only satisfaction for you is doing it yourself

Nice work man!

So any way to disable traction control only?

Don't all ABS equipped cars do a self test each time the car is started and driven? My J30 does.. if you listen carefully you can hear it once the vehicle speed gets above about 15km/h, you can also feel it through the brake pedal if you happen to have your foot on the brake pedal at the time. Doesn't make any loud 'knocking' noises though.

i guess its one of those nissan noises that are supposed to happen but dont sound nice... like my timing chain rattle on a cold start up... normal, common but annoying...

maybe you could dynamat the area the sound is coming from or something...

you dont have to apologise for long posts! i'm sure all the j32 owners out there would be happy to read your findings!

Brainy - in fact after looking into the J32's modules in depth, there is a theoretical way to disable traction control without loosing the ABS by means of a switch, its quite popular to fit a switch in the states but I'm not sure what effect this might have on the rest of the diagnostic functions/warnings on the car because as traction is tied in with the vehicle dynamics control, chances are there will be unwanted side effects.

Sonicii - Yeah its true that most (if not all) ABS equipped cars so have some form of self test which vary from make to make but yeah the operating noise in this case doesn't sound natural or normal but again it could be an isolated Nissan issue.

Joe - Dynamat sounds like a decent way to address the issue because of its thermal resistance, but in this case the solution could even be as simple as exchanging the grommet / bushes that connect the ABS module to the bracket and firewall.

If I manage to dig up any further dirt or manage to fabricate a solution I'll be sure to mention it.

Yeh I had that twice now on the car.. But I never really thought too much of it.
It only lasted around 2 seconds and I though it was one of those testing things.
It only happened within 10 seconds from the start of the engine while reversing out from my garage.

I brought the car into the 1000km service today and they said the car was in fantastic condition.
Although it seems like the little tapping noise was coming from the wiring behind the center console.

Also they have done the side airbag strap recall work.
It only lasted around 45mins so I would say it was pretty good.

joe....

beaugus - credit to you on some decent investigative work! Thats some Sherlock Holmes sh*t there!

Gotta say, with my ABS, I've never noticed anything like this self-testing noise

Whats it like?

On my J30, it is just a short pump noise (whirring type noise) from the ABS unit, however the J30 has the ABS unit is mounted just behind the right headlight, the J31 is mounted on the firewall, so that would make any noise more audible in the cabin. but I can't say I have ever heard any noise from the ABS unit on my J31..

i have never heard anything either...



i guess it would be like a knocking sound? "J32 Maxima - Knocking Resolved"

a detective you are not dan...

I know my A33 makes a noise every time I leave my driveway... Thanks to you, I now know the sound. Only happens every time the car is started and driven for a second or two. Sounds almost like someone applying there foot on the brake with dirty discs.

Oh and beagus, congrats on finding out your issue. You did some serious investigating! If you were a mechanic, you would have my business lol

^^^^^ hey! i get that sound too ed! like a dirty screachy sound for like 1 second when i start up after a long period... so thats what it is!

Yeah, it took me years to find an answer to that noise, thanks again Sonicii!

Great post, Thanks mate