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I have a 99 D2 Equipped with ACE that I tried to fix one problem but seemingly have caused another. Since buying the car earlier this year the ACE system has worked flawlessly minus pretty constant leaks where the hoses meet the reservoir. So I finally got around to replacing the leaking hoses along with the reservoir itself. Initially, 30s after starting the car I would get the amber ACE light which sets code 20-04 Pressure Control Valve Fault. This morning when I went to move the car into the garage I was met with the Red flashing ACE light. I attempted to bleed the system with my nanocom as I figured there could be an air bubble trapped in the system but that did not correct the issue. I had done some research on the forums where people recommended running generic synthetic power steering fluid as it helped quiet the pump but I'm wondering if this fluid I used may be thicker than the original fluid, causing the pressure to exceed the approved values of the system? If the issue persists I will probably swap the fluid again to the proper ACE fluid to see if it will correct the issue but wondered if anyone else had experienced something similar?
I've been running regular power steering fluid in mine for over 10 years without any problem what so ever. It can be a little noisy on start up when it's below zero, but other than that it's been fine.
Double check the hoses are all connected to the correct places? Air in the system will usually work it's way out with a little cornering in a parking lot
That generic power steering fluid is almost certainly the problem. The ACE system is incredibly picky and requires the specific ATF it was designed for, usually Dexron III. The wrong fluid viscosity will throw the pressure readings off and trigger those exact valve faults.
Swap it out for the correct ATF first. Bleed it thoroughly with your Nanocom again after the fluid change. If the code clears, you've found the issue. If not, you may have introduced air into the valve block itself, which is a much bigger pain to purge.
There is no usage of “ATF” in the Land Rover ACE system. Once again @Bengoe is 100% wrong with his replies. He’s an AI Chatbot that’s posting here and on the Defender L663 forum frequently. Don’t listen to this moron.
I think I ended up having an air block in the system. After driving in a figure 8 in a gravel parking lot several times and starting and restarting the car the error cleared and has not returned.
ACE Warning Light After Reservoir Replacement
