4wd/2wd switch

[Ottdurr]

 250t rx-four here 

I've trawled through the old forums and everyone basically says no "fun switch" can safely exist in this car and if you wanna make it 2wd you have to remove front driveshaft or something serious like that. 

It's been a couple years and I've got a bit of an idea, hear me out.

Ive had a search and a lot of people have reported intermittent faults with the 4wd light coming on and the car going into 2wd mode. I've had this fault too, only occasionally and it goes away if i restart the car. The error on the japanese infotainment screen roughly translates to "Your 4wd is no longer working but you can still drive the car in 2wd, please see nissan dealer to repair 4wd".

It seems for some people the issue is caused by a faulty relay in the front of the car under the air filter, and replacing it could fix the intermittent fault. I tested mine by removing that relay and the 4wd error light came on and the car was effectively 2wd. I think this relay controls ABS too so maybe the car loses its abs too. 

 

My question is, why don't we just hook up a dash mounted switch in line with the wires going to this relay to disable or enable it for a "fun switch" to safely make our cars 2wd at our will? 

 

I've read some of the people on this forum reckon something like this will harm the clutch for the 4wd but why would the infotainment screen say it's okay to keep driving with a similar fault?

A fun switch wouldn't be pressed every day anyway so surely it's not that bad? 

 

[KiwiRS4T]

16 minutes ago, Ottdurr said:

 250t rx-four here 

I've trawled through the old forums and everyone basically says no "fun switch" can safely exist in this car and if you wanna make it 2wd you have to remove front driveshaft or something serious like that. 

It's been a couple years and I've got a bit of an idea, hear me out.

Ive had a search and a lot of people have reported intermittent faults with the 4wd light coming on and the car going into 2wd mode. I've had this fault too, only occasionally and it goes away if i restart the car. The error on the japanese infotainment screen roughly translates to "Your 4wd is no longer working but you can still drive the car in 2wd, please see nissan dealer to repair 4wd".

It seems for some people the issue is caused by a faulty relay in the front of the car under the air filter, and replacing it could fix the intermittent fault. I tested mine by removing that relay and the 4wd error light came on and the car was effectively 2wd. I think this relay controls ABS too so maybe the car loses its abs too. 

 

My question is, why don't we just hook up a dash mounted switch in line with the wires going to this relay to disable or enable it for a "fun switch" to safely make our cars 2wd at our will? 

 

I've read some of the people on this forum reckon something like this will harm the clutch for the 4wd but why would the infotainment screen say it's okay to keep driving with a similar fault?

A fun switch wouldn't be pressed every day anyway so surely it's not that bad? 

 

[Sorry just realised you have an M35. Try and find a manual for it but this is the procedure for a WGCN34]

[Do not remove that relay]?. This is the approved procedure  outlined in the WGNC34  manual:

Locate the "air bleed" wire behind the drivers kick panel, it's a plug with a single wire either side (usually green socket, white plug).

 

In my S1 Stagea its a very small black plug taped to a loom with a single yellow wire with a green trace going to the plug and a single black wire going to the socket.

 

Disconnect it.

 

Start car. As key comes back to the ON position, within 10 seconds, depress brake pedal 5 times, 4WD light will start flashing to indicate you are in 2WD mode.

 

You need to do this every time you start the car.

 

To go back to 4WD mode, turn car off, reconnect plug and off you go.

 

And if you plan to do this a lot you can put a switch in somewhere.

 

 

 

[Ottdurr]

2 minutes ago, KiwiRS4T said:

Do not remove that relay. This is the approved procedure  outlined in the manual:

Locate the "air bleed" wire behind the drivers kick panel, it's a plug with a single wire either side (usually green socket, white plug).

 

In my S1 Stagea its a very small black plug taped to a loom with a single yellow wire with a green trace going to the plug and a single black wire going to the socket.

 

Disconnect it.

 

Start car. As key comes back to the ON position, within 10 seconds, depress brake pedal 5 times, 4WD light will start flashing to indicate you are in 2WD mode.

 

You need to do this every time you start the car.

 

To go back to 4WD mode, turn car off, reconnect plug and off you go.

 

And if you plan to do this a lot you can put a switch in somewhere.

 

 

 

Very interesting, thanks. 

Is it the same for m35 stageas though? 

[KiwiRS4T]

2 minutes ago, Ottdurr said:

Very interesting, thanks. 

Is it the same for m35 stageas though? 

Yes just noticed that and amended my post. The answer to the above is I don't know!

[GTSBoy]

But, given that it is still ATESSA, and the pre-load air bleed wire thingo was added at the R33 vintage (having not existed in the earlier R32 vintage ATESSA), it is reasonable to expect that they did not throw the pre-load back on the scrapheap and that you would still need to handle it.

It is also reasonable to expect that the m35 ATESSA computer would be smart enough to safely bleed off the pre-load pressure in the case of a fault. Thus, it would be "Your 4wd is no longer working but you can still drive the car in 2wd, please see nissan dealer to repair 4wd". Pulling the relay, if it triggers a fault that results in the above message, would probably be fine, if that's all it did. But if it also disables other systems on the car then it's probably not a great idea.

Beyond that, I don't actually know, I'm merely throwing up some thinking material.

[Ottdurr]

2 minutes ago, GTSBoy said:

But, given that it is still ATESSA, and the pre-load air bleed wire thingo was added at the R33 vintage (having not existed in the earlier R32 vintage ATESSA), it is reasonable to expect that they did not throw the pre-load back on the scrapheap and that you would still need to handle it.

It is also reasonable to expect that the m35 ATESSA computer would be smart enough to safely bleed off the pre-load pressure in the case of a fault. Thus, it would be "Your 4wd is no longer working but you can still drive the car in 2wd, please see nissan dealer to repair 4wd". Pulling the relay, if it triggers a fault that results in the above message, would probably be fine, if that's all it did. But if it also disables other systems on the car then it's probably not a great idea.

Beyond that, I don't actually know, I'm merely throwing up some thinking material.

Yeah it seems like it will work right? Keen to hear some more opinions. ABS being disabled won't be a huge safety problem seeing as the primary use for the "fun switch" would just be for whipping it round a gravel pit or something 

[BK]

We've been through this a few times now, but basically it's like this:

R32 is the only Attesa that has a single solenoid for pressure operation, and therefore no transfer case preload. Everything after R32 vintage Attesa has dual solenoids as far as I'm aware (definitely on GTRs).

One, the failsafe solenoid, keeps a small amount of pressure to the transfer therefore adding transfer case preload.

The other second solenoid, is for the normal varying torque split control. The failsafe solenoid is the reason in post R32 models you can't just pull the fuse and electrically turn it off like an r32. 

Kiwis method for 2wd activation in the post R32 cars depressurise the failsafe solenoid also, taking all preload off the transfer, therefore being totally ok for your transfer. If you don't do it this way, your transfer friction plates WILL be destroyed as they'll be dragging.

Your only way to get 2wd safely for you is how Kiwi mentioned to do it.

16 hours ago, GTSBoy said:

But, given that it is still ATESSA, and the pre-load air bleed wire thingo was added at the R33 vintage (having not existed in the earlier R32 vintage ATESSA), it is reasonable to expect that they did not throw the pre-load back on the scrapheap and that you would still need to handle it.

Also the Attesa motor activation connector exists in the R32, still the same method to bleed it as the 33/34. But as mentioned above they did not get rid of transfer case preload on later models.

[Ottdurr]

Thanks I think m35s are different again though? 

[BK]

You either have 2 solenoids or one. Stageas are 1996 onwards, so pretty sure they won't be using the R32 single solenoid setup. It's easy to check on Nissan fast, so should be able to find out. Better yet is to check to setup under the right rear guard area. I really doubt the M35 will have only one solenoid, as they are very R33 based.

Do you have an active rear diff ?

[Ottdurr]

Nope it's the factory open diff. 

 

Does the pre load disengage when the engine is turned off? 

If so could you turn off car, disconnect power to solenoids while car is off and then turn on car and there is no preload? 

[GTSBoy]

Why look for alternatives when the actual answer has probably been posted on this site 50 times?

[BK]

Exactly. From this very section...