So I just started to get the flashing "Tarmac" light. I've been researching the ACD but have not been able to find the answer to my question. So my fluid reservoir is full. The manual states to check the fluid after 90mins or more. After waiting that time frame and checking, it is full. Checking the fluid before the 90mins, right after driving, the fluid levels drops from full to almost min level. So with this check I assume the pump is working properly. Also, the flashing "Tarmac" light doesn't flash all the time. It starts flashing about after 30mins of driving. Then when it flashes its intermittent. It flashes for a couple seconds then stops for a couple minutes then starts again. Wondering if the pump is starting to die, or since fluid still seems to be moving, maybe the sensor is going bad. Any thoughts?

 

Can you still switch modes?

A blinking ACD light normally means that the ACD motor is not functioning. When my ACD pump when up, it didnt blink; instead I got the AWC service indicator light (on a 2008) in the center dash and I couldn't switch driving modes. Either way, swing it by your dealer since the ACD warranty was extended to 10year/100k miles and they'll determine if it needs the free replacement.

 

prolly dieing pump.

 

I am in the exact same boat. Flashing tarmac and a ton of ACD codes in the ECU. BUT NO AWC SERVICE light. This means that the pump is failing to keep the pressure up, and is cycling. However, it has not failed completely and there is a time period that it is allowed to work to try and resolve the pressure. A few seconds I believe. Until it cannot build up the pressure at all, it is technically not dead. Take the car to a dealer so they can record the ACD codes, and this will help things move quicker when it dies. You may even get them to replace it before full death. As mentioned, they are covered for 10 years 100kmi because they are made like crap and are located where road moisture and crap hits it. They corrode fast and badly. Most die before a new car reaches 40kmi. I am going to try and get mine replaced before full dead. My car is also modified to the tilt. This should be fun

~Jaraxle

 

Thanks for the info. It's been a few days now and the light hasn't flashed in a while. Any idea why it doesn't make pressure in temps over 85degreesF?

 

I have been having the same issue. Mine started flashing last spring and did it very randomly throughout the summer. Then stopped flashing in fall and winter months (colder temps below *45) and has now started flashing since about 2 months ago (warmer temp's above *50) . It now flashes all the time. Starts flashing as soon as I turn out of the parking spot and I hear the pump whining, then stops for a couple seconds (at this point I could change the modes from tarmac to snow to gravel) then a few seconds and...Bang flashing again. I took it to the dealer and they basically said come back when you get the service awd light and at that point we could change the pump but not before the service light comes on. So I guess its just a waiting game at this point.

 

I am guessing the warmer temps thin out the fluid so it is more likely to find its way around the seals through the corroded dips in the sealing surface. Colder temps mean thicker fluid so it is easier to keep pressure. Just a guess.

~Jaraxle

 

I thought that was the case. But does your pump still start up when you turn your ignition to ON? Mine doesn't and it doesn't activate with the gas pedal method either. So with the pump not starting, I don't know how it's still making pressure?