When the Mitsubishi Pajero NP is working correctly it is a brilliant vehicle however I did come upon a frustrating problem when the 4wd error light started flashing.
I want to share my experiences with what appears to be a common problem for the Mitsubishi Pajero 4WD and that is that the 4wd select system sometimes fails to engage or disengage the 4wd and instead displays a failure mode where the centre 4wd indicator light flashes. This can occur when actually switching the mode in or out but can also just occur on it's own.
The flashing light indicates that the system does not know what state it is in, either in a particular mode or not. This is because the sensor switches that get activated by the various movements of the 4wd mechanism are not passing back the correct state information. It is completely understandable that switches wear out or get corrosion in them that mean they don't signal the actual state they are in.
For the first year of this problem I found that it occurred mostly when I had not used the 4wd modes very often. The switches must get corrosion on their contact surfaces when not used so that when they are switched they are not making good contact internally to pass a current through. In this case switching the switch regularly keeps the contact surfaces cleaner and prevents or even corrects the problem. I found that sometimes if I was in 4wd and tried to switch out of 4wd that the error light would flash. When this problem occurred I turned off the car, put the selection back into 4wd and then turned the car back on. It would then usually not have the error since the error occurred when coming out of 4wd. I would then try to take it out again and it would usually work the second time. Sometimes I might have to repeat this a few times before it would work. Once I got it to work it would usually be ok for a month or so after. I did take it to the Mitsubishi dealer at one stage, however because the problem was intermittent and went away with a bit of fiddling they said they couldn't be certain how to fix it, so I just put up with my solution.
This worked for about a year and although it was sometimes annoying at least I had a way to deal with it. Unfortunately eventually the 4wd select problem went to a new level. I could be driving along in 2wd and the system would suddenly decide something was wrong and go to the error mode where the centre 4wd indicator light would be flashing. At first the old method of turning off putting in 4wd and turning back on worked but after a while the light just flashed constantly and nothing I could do would make any difference.
So I took it back to the Mitsubishi dealer who spent a day looking at it and finally said they knew how to fix it but it would cost nearly $1000. Basically the switches had finally got to a point where a bit of use was not enough to clean their contact surfaces. The good part of this was that it was easy to test and isolate the problem. The bad part was that each switch costs around $120 and there a 5 of them! Adding 3 hours labour to replace them resulted in a bill over $900! But the good news is that it is fixed, I haven't had the problem since.
I feel like I may have got a bit ripped off, the switches are very small and don't look like they would cost $120 each but you just don't know with some parts. I also think if you knew where the switches were they would not take 3 hours to screw out and screw in new ones. As far as I know they are all around the central gearbox assembly but I am not certain just how hard they are to get to.
Anyway I wish someone had told me all this stuff right at the beginning. I might have been able to get this under warranty instead of waiting a year, I might have been able to shop around with mechanics to get it done cheaper or I might have been able to figure out how to do this myself and save a lot of money.
Anyway I hope this helps someone. The Pajero really is great when it is working properly.