4WD Selection Fault - SOLVED

[bitz]

Help,have a 05 nav,9months ago 4wd indicator was flashing on dash all the time although truck would engage 4 high or low as selected.searched the forums and found others with similar problems and had local mechanic change the three switches on the transfer case,problem solved.4weeks ago same problem returned although this time I can not select 4wd at all.took back to mechanic who said switches looked fine and sent truck to auto elec.auto elec says he can not access Nissan computer to diagnose fault.says Nissan is the only manufacture that they cannot access.truck must go to Nissan,does this sound right?

 

[doc]

Sad, but sounds about right. I'd book it in to Nissan for diagnosis only - tell them you want to know what it wrong and will make a decision of fixing it then. Shouldn't cost you too much.

 

[Old.Tony]

Check your ABS sensors. Any damage (including the teeth being filled with muck) will cause this.

 

[skippyjason]

Hi Tony. Where are the ABS sensors located? I have EXACTLY the same issue.. 4WD engages (Hi and Lo) but the 4WD indicator flashes on the dash.

Cheers

 

[Arty_74]

Hi Tony. Where are the ABS sensors located? I have EXACTLY the same issue.. 4WD engages (Hi and Lo) but the 4WD indicator flashes on the dash.

Cheers

Sounds like your switches need replacing on the transfer case, exact same thing happened to mine, Nissan replaced them as the car was still under warranty, been working fine ever since

 

[Old.Tony]

ABS sensors are on the axles out near the wheels. Checking the transfer case switches might give you an answer. If the ABS has developed a fault, it may not allow 4WD to engage at all (which has been experienced by others before). If you can successfully get it into 4HI and 4LO, it's more likely on the transfer case.

 

[skippyjason]

OK. I'll have a look. However I replaced all 3 switches on the transfer case 18 months ago after the 4WD warning indicator was flashing on the dash.

I understand those switches are problematic - but I didn't think it was likely that the switches would fail again so soon!

Whats the test for them (aside from putting them in the vehicle and checking the operation)? Is there a procedure for cleaning them?

The switches and electronics are supposed to help, but the rate at which they give false positives and 'dont know' readings leaves me to think these electronics are overengineered to the point where they cause more issues than help.

Eg: I have a low oil indicator coming on periodically on my dash, although the car has just been serviced and the oil level is fine. The low oil indicator was periodically firing before the service also..

 

[Old.Tony]

A periodic flash of the oil indicator is very likely to be a loose/intermittent connection on the oil pressure sender. That is unusual, and points to something like a fluid - possibly a brackish river, salt water or an unusually dirty water splash on a road. If the oil pressure sender has been affected, the transfer case - sitting low down and behind the front wheels - could also be affected in the same way.

So, next step - pull the electrical connections apart, clean and reinsert and see how it goes!

You might also want to go through this process with the relays in the distribution box in the engine bay. They're notoriously sensitive to fluids - deep water crossings or even the old Gerni can cause problems with them.

 

[bitz]

I finally got the chance to have a look myself after the less than satisfying result from my mechanic and auto elec.after working through the fault codes with a multi meter,found the problem in 20 mins.broken plug on wait detection switch.now works fine.

 

[Dave]

Nice work. Always good to hear outcomes.

 

[Old.Tony]

I've edited the thread title to reflect the problem and that it's resolved - makes it easier for others to find when searching. Excellent news!