I have a quick question, when all 3 ACD lights are on, I know the pump is out. but what does the AWD do then? so does the car just not distribute power side to side and front to rear anymore? and also, does it just default to tarmac mode? or how is the AWD power distribution affected if pump is out?

 

You should be safe to drive on it (Had a friend who had a dead ayc and acd pump in his Evo 7 and he drove it for 5 months before having them rebuilt). You'll obviously lose the performance benefits and possibly the safety benefits of a smarter traction control system. I don't think it really defaults to any mode, but if it's anything like AYC you just have an open center diff now essentially.

Not sure how the torque splits. If AYC fails in a second generation Evo I recall reading on lancerregister that you just get 50/50 with an open rear diff so I imagine the torque split on a failed ACD is also 50/50.

 

i believe i read somewhere that if your pump dies default setting is tarmac. not 100% but i think. my pump has been bad 1 1/2 yr now and its still not fixed. It was bad when I bought the car so idk what a car with a good acd system even drives like lol

 

You will lose functionality of the center diff because no hydraulic pressure. You still have mechanical AWD, just no center locking diff is my understanding.

I drove for quite sometime before I got my pump rebuilt

 

Not sure if this Applies to you but if the fuse on the battery goes the light come on because the power to the acd pump gets disconnected. That happen to me change the fuse and it worked. Just Something to look at.

 

This. The system doesn't default to one of the modes, it is simply off. So you still have AWD, you just have an open center diff. The car will behave much differently when driving aggressively, so pay attention to it. But it will not hurt anything to drive it until you can fix the pump.

 

ben IX, specifically, what fuse was it?

 

If I recall correctly from working on a friends E9 the fuse is on the positive battery terminal underneath the plastic covering.

Just did a google search to double check. I seem to be correct.
https://www.evolutionm.net/forums/ev...lp-needed.html

 

Thanks