hello everyone, first post on this website and i have my fingers crossed for an answer 🙃. purchaced my 2011 d5 r-design xc90 to use it for four wheel dirivng intentions. i purchased some mud terrain tyres for it and got into four wheel driving.

i can get this car absolutley everywhere the land cruisers and pajeros go only downside is if i attempt to drive through some very deep water or up a slipperly steep long hill after about 1km the computer kicks the car into limp mode meaning i have to roll the car back to get off the trail and let he car sit to give the compouter to reset, my only issue is it makes progress very very slow. the thing i was wondering is it possible to buy some sort of aftermarket ecu chip to dissable the limp mode setting on the car.

regards
oli

 

The vehicle is not designed for off-road adventures. You are probably getting the electrical connection at the rear haldex unit wet causing the limp mode. At any rate, the AWD system in this vehicle is not designed to go "muddin'".

 

yes tony, you are right the car is not designed for hard off road! that being said i haven had any diff, transfer case or transmission problems, i will continue to hope for an answer for the limp mode but after calling a couple tuning places here in Sydney and them having no idea it seems like i may have to bite the bullet and look at selling my beautiful xc90 to purchase a more dedicated 4x4.

 

I guess they get hot, as the only way they can transmit power is clutches, or maybe they time out after using traction control for a certain amount of seconds (like due to brake temperature). I never thought about prolonged Haldex operation being a major practical problem, but in the next-to-last episode of "the grand tour" with Jeremy Clarkson et al, they demonstrated how limited these systems are. They were using a Porsche Macan and Range Rover Velar and the Macan at least went into limp mode any time it was offroad. Maybe it was both of them, but I don't really remember.


Okay, I looked it up, so the Alfa Stelvio also went into limp mode before they ever got into the woods. it wasn't even included in actual offroad driving.

 

Back in the old days, you used to hear about "four wheel drive" or "4x4" which typically meant a pickup truck, Suburban, Blazer, Bronco, Jeep, etc. Those vehicles were definitely built for hard use off road. You could run them through mud holes and up hills with a bit of brute force.

Now a new term is floating around, "all wheel drive" or "AWD". This is an on-demand system at each wheel. The vehicle is mostly either front or rear wheel drive with the extra drive wheels when needed. Volvo refers to theirs as AWD and Mercedes calls theirs 4-Matic.

These latter two systems are not designed to go off road but only a limited push when needed in bad weather.