4wd error when in 2wd

[awdav1]

I've searched all over the net for this and people have had the issue but not on an NP300 - only seem to be D40.

So 3 times in past 3 months I am driving along in 2wd once was 50 down a bitumen road, once was 80 on a bitumen country road and again today bitument doing 2. KMH by the way. Each time the 4WD error warning come sup on the dash. Great....but I'm not in 4wd.

Switching to 4-Hi does nothing....error still shows and it won't shift to 4Hi. once I stop and restart.....the issue goes away.

The car is out of warranty so no point throwing it back at the dealer. I did call Nissan and surprise surprise no dealer I spoke with has ever heard of this. No doubt not even an error code will show so I'm loathe to take it to a dealer if I'm honest.

I want to sell the car (as in I am advertising it now) and not for this reason, it's purely conincidental that the day I advertise it, it throw the error again. So I need to fix the issue without A. spending a tonne of money on a dealer who wants to throw parts at it and 2. I don;t want to sell it to someone only for them to come back to me and whinge. Therefore ignoring the issue won't help either.

Any ideas where I could start ? I hear about switches on the transfer case but I don;t know what they look like. '

 

[BarneyB]

I don't know the specifics of the system on an NP300.
But with the D40 that sort of problem is very often related to one of the wheel speed sensors.
They are prone to getting whacked by debris when off road & triggering 4WD system issues.

I'd start by removing the front wheels & having a look at the wiring that runs down to the back of the hub. Again, I don't know how it is on an NP300 but I'd bet a six pack it has an ABS sensor at each corner.
Look for a wire/cable (usually has stout rubber insulation) that is loose or dislodged, cut, chaffed... or covered in schmutz.

Failing that, go after the loom connections at the gearbox & transfer case.

The fact that it refuses to engage Fun Mode tells me it's missing a required input signal (i.e. it has a check list it goes thru before giving you 4wd)

Don't suspect it's a big expensive problem yet... could be something simple-ish.

 

[awdav1]

Don't suspect it's a big expensive problem yet... could be something simple-ish.

Thanks BarneyB,

actually you gave me an idea with this. Today it occurred after I had washed and detailed the car. I gave all the wheels a really good power wash. I wonder if it was coicidence or you're onto something. The first two times didn't involve washing/water but its possible theres a funky connection and water helped today's episode.

I did also wonder....I have engaged 4WD maybe 3 or 4 times since I have owned it (150,000 kms or just under 100,000 miles) could I be low on transfer case fluid/oil to the point that it sometimes detects I don't have enough or am I way off ?

 

[Old.Tony]

The most common reason for this is the ABS sensors with some gunk in them. And that gunk usually comes from a wheel bearing that's letting go (it heats up, liquefying the grease, and combined with the metal flakes makes a nice paste that sits in the ABS rings and blocks them). It's happened twice to me. Replaced the bearing - problem gone (the ABS ring is part of the bearing too, along with its connector).

There are 2 ways to test:

1) Find a smooth, flatish corner (so you don't need to use any throttle) that you can take in both directions at a moderate speed (50-60km/h) without making the tyres squeal. Take it one way, listening to the sound the wheels make. Go the other way and listen again. If there's a louder sound when you're turning left, your right hand bearing is going.

2) Jack up the car lifting a wheel completely off the ground. Consider using a jack stand for safety. Give the lifted wheel a good shake - it shouldn't have any 'give' in it in any direction.

Bearings aren't expensive on eBay.

 

[awdav1]

Thanks for the replies to date. I have checked the ABS sensor wiring for any obvious damage and thus far to me they look in tact. I'll pop the car up on some quick jacks and check the wheel bearings next.

 

[awdav1]

So update. Went in to service today at Nissan for a 150K. They did a full scan and they can see the 4WD error twice. Can't seem to find any valid reason why. All wheel sensors and bearings are perfect. Cleared the codes for me. Found a few codes actually....found some parking sensor ones but I reckon that was probably when I had the rear tub replaced and the panel shop moved the car with the sensors off the car. Found a few engine ones but they never threw me a code (camshaft position sensor) and I've never had engine problems and some battery ones when I replaced the battery around 4 months ago. All codes cleafred now...we'll see what prevails.