Vehicle was in cold weather, ayc system light turned on. I checked the forums and found that this is a common issue that indicates the pump is bad. This is a very common problem.

- Ridley Park, PA, USA

It was a cold winter day, I started driving my evo to a nearby grocery store. Enroute, the AWD system would throw a warning and a dashboard light lit up. I was concerned, stopped the vehicle and found no leaks or no weird noises. The vehicle was unable to shift into snow/tarmac/gravel mode. Fortunately I was not stranded on the road side. Upon further investigation I came to know that the acd pump failed and hence it threw an AWD error. Its costing about 2200 dollars to fix this issue.

- Royal Oak, MI, USA

When starting my 2008 Mitsubishi Lancer evolution gsr, I received a warning message on the cluster display showing a yellow-orange symbol that shows 4 wheels connected by axles and the middle-shaft, where the front two wheels are facing at an angle to the side. The error code read as C161E: Dtc C161E: Electric pump relay circuit system (stuck). This has become a very common issue with the 2008 Mitsubishi Lancer evolution. So common that when you search for the code C161E, you can find countless forum discussions on multiple websites commenting on the frequency of this issue. Including myself, a single discussion identifies at least 48 unique cars, 42 of which are the 2008 model year, where the acd pump failed, all of which having driven fewer than 75,000 miles and nearly 60% with less than 50,000 miles (www.evoxforums.com/forums/showthread.php?T=58221&highlight=C161E&page=1). Several of these vehicles required multiple replacements of the same part. This problem affects the safety and effectiveness of the vehicle's all-wheel-drive system, likely including the vehicle's traction control and needs to be recalled immediately.

- Pearl River, NY, USA

Loss of electronic stability control. Ayc/acd pump failure due to poor engineering. Car has no stability control and driver is more likely to lose control in severe weather conditions.

- Tomah, WI, USA

Active yaw control (ayc) and active center differential (acd) pump failed. Not covered under power train warranty pump was corroded and could no longer produce enough pressure. Pump in located directly behind passenger rear wheel exposed to water, salt, and other road debris.

- Draper, UT, USA

Went to dealer for transmission check and after a mile awc light came on they said it had nothing to do with computer update they did.mind you my tranny was going bad and dealer did not want nothing to do with it even under warranty.

- Brooklyn, NY, USA

Electronic stability control / S-awc (tarmac/gravel/snow) inoperable. Terrain selection can be performed at 0mph however when the car is placed in motion: Forward / reverse, the instrument panel indicates there is service required in the AWD traction control system. This is apparently a common problem, from the multitude of complaints for this specific issue posted here.

- Doylestown, OH, USA

Acd (active center differential) pump has failed and without this pump providing pressure to the all wheel drive system, the vehicle gets stuck on driveways at a stop where the tire and wheel packages are on different elevated surfaces. The reason the pump has failed is due to placement of the pump on the vehicle. Mitsubishi has designed the vehicle to have the pump to be located directly behind the rear passenger wheel. Due to this, while driving on severe weather roads (particularly snow salted roads), the dirt, water and salt gets kicked up to the position of the pump which corrodes the fittings and the pump itself. This then causes the pump to fail over time. It could have been easily remedied by relocating the pump or anti-corrosion protection and better sealing. Being located in southern California, I would have thought that this would have never happened to me, but even driving only twice through snow roads in the past 3 years has corroded the pump to failure. Mitsubishi has denied that this is part of the power train warranty, which means it will be a $2000+ dollar fix.

- Upland, CA, USA

Acd (active center differential) pump failure at 43000 miles. Was repaired under warranty but failed again 2 months ago (less than 60000 miles) January 2014. So the new pump installed did not last for more than 15000 miles. This is a common and known issue for all Mitsubishi models equipped with that acd stability control.

- Newport, VT, USA

As many evolution owners who live in the midwest can also attest, my example now joins the club of models with defective asc/ayc pump failure. The pump fails when outside temperatures run close to freezing, on top of the unit corroding, and evolution owners are being forced to shell out $1800 minimum to Mitsubishi for the pump alone, not including labor. I believe this has only occurred to my Mitsubishi after six years because I've been very good about keeping the underbody clean, and it's nearly always parked in a heated garage. Without the proper functioning of this integral drivetrain equipment, we aren't able to control power delivery front to back and the vehicle computer goes into a type of limp mode where no control of the delivery of power to the wheels is possible. Of course the brakes work and the throttle works, but whereas the vehicle used to be selectable for snow or gravel modes, greatly improving traction and the ability to limit slippage of the rear wheels, we instead stare at a digital readout instructing us to service the unit that's corroded and the pump has overheated and also failed as a result. www.evoxforums.com and www.evolutionm.net has plenty of other customers who are belong frustrated with this issue that Mitsubishi doesn't want to address. Nearly all of us have spent good money on a vehicle we thought would be a solid performer in both the dry, wet, and snow and instead, some owners have to pay not once to remedy this unit that's failing on all our cars, but I've heard of owners having to do it two and even three times. Owners are trying to save money by breaking down the unit and repairing the internal motor. People are experimenting with ways to prevent the units they purchase to prevent them from rusting and corroding. Please please please contact Mitsubishi and help us??

- Chicago, IL, USA

I started my car and the awc service light came on. I came to a controlled stop, and restarted the car per the instructions in the vehicle manual. Upon restart, the same service light came on. After the dealer ran a diagnostic, it was found that the high pressure pump for the active stability control system had failed. I was told that this part was not part of the drive train and would not be covered under warranty. The day the pump failed it was very cold and there was packed snow on the roadways. If I was driving at higher speeds and this pump had failed, I believe the automobile would not have behaved as expected with the awc stability active.

- Windsor, CT, USA

This is report of a known failure by Mitsubishi motor Corp. At 50,800 miles on 12/17/2013 my cars super-active center differential (s-acd) started blinking at me. It would not allow changing of the settings anymore for tarmac/gravel/snow. Immediately there after, the driver information panel popped up with a yellow "AWD service required" indicator. I brought my car to nashua, nh Mitsubishi/Hyundai for diagnosis on 12/19/2013. There they applied tsb-SC11-002. This unfortunately did not resolve the issue. I was then informed that the car required a replacement acd pump and was quoted $1,995 for the repair, which confused me due to the fact that my car was still under manufacturers power train warranty, and a pump, that controls the AWD system of a car, seems to be power train related, at least in my eyes. The North East regional representative was contacted on my behalf by the dealership to request coverage of this item, which was ultimately denied. This is a severe safety issue, as the car no long handles properly in conditions it was designed for. I am no longer able to select the car for snow, living in the North East, driving a car marketed in the North East, this is a huge problem. To further the issue, this problem is well known by Mitsubishi, it has been documented well, tracing all the way back to cars manufactured in 2006. 90% of all pump failures could be completely eliminated by adding a seal to stop corrosion inside the pump which leads to the untimely failures. If no recall is issued for this failure, at the very least, Mitsubishi motors should be forced to cover this under power train warranty for 5yrs/60K miles. Instead of limiting it to 3yrs/36K bumper to bumper. Link to documented cases - forums.evolutionm.net/evo-X-general/655162-those-you-acd-pump-failures-merged.html.

- Nashua, NH, USA

Because of the location (rear wheel well) and design of Mitsubishi's active center differential pump, they are prone to failure. Several factors aid in the galvanized corrosion of the pump's internal plate, some of which include temperature fluctuation and weather. Vehicles that are in service throughout the snow belt states in the us and well into Canada seem to be the most affected. My vehicle was just outside of the vehicle warranty range for time but very well inside the range for mileage.

- Medford, MA, USA

Started my car 1N 30 degree weather and let it idle for a couple minutes pulled out on my street where I live and my acd/ayc quit working I had a picture of all for wheels on my info center with the front wheel on an angle. Took it to the dealer and they said my all wheel drive pump was bad and that since my car is an evo it was not covered.I paid to have it fixed and got my car back and my timing chain broke dealer said it was not covered also since it was an evo $3500 in 1 month.

- Lake In The Hills, IL, USA

The S-awc or super all wheel control system on the Mitsubishi Lancer evolution helps the all wheel drive to actually work. I had a service message pop up on my car with the S-awc system being indicated. After reviewing the car's manual and the internet to help diagnose the issue of why it was causing it, I'm told there is an ever-increasing number of vehicles with this S-awc pump failure either in super cold conditions or very hot conditions. This has the potential to be very dangerous if the pump ends up going out when someone is making a turn or is relying on the all-wheel drive to actually work in adverse conditions. The only notable change is a difference in steering feel and the service message popping up after several minutes of driving, though due to safety reasons, I am trying not to push the car too hard until the problem is addressed.

- Red Lion, PA, USA

The car is displaying an S-awc service light, it has yet to be diagnosed by the dealership but I have brought it in previously for the same issue. Looking online there is a whole mass of forums stating that at 40,000+ miles the ayc pump breaks. This seems rather suspect given so many individuals are experiencing the same problem within the same time span. Mitsubishi has been reportedly turning down warranty coverage for this under their power-train warranty, while I am unsure if they will do the same for me, the issue is seemingly prevalent enough that they should know about it.

- Las Vegas, NV, USA

On Monday 2013 April 22 I [xxx] (owner of vehicle) was getting off my shift at approximately 0700 hours from bethel twp pd; where I work as a patrolman. The temperature was fairly mild 60-65F, I started my 2008 Mitsubishi evolution 10 to let it warm up like I always have for approximately ten minutes. I put my evo in gear and on the center L.E.D. screen I received the C161 message which indicates S-awc failure or super all wheel control. This effects everything with the cars' suspension stability, yaw control, and the "smart breaking" feature. For an un-experienced driver this could be catastrophic. Knowing the importance of this I was forced to bring the car to springfield Mitsubishi in springfield, pa. 1(484)574-8434. Now I'm stuck with a $2132 bill and the car is still in the lot because I don't have the $2132 to "shell" out. I went to two separate forums www.evoxforums.com and www.evolutionm.net, and I don't know whats scarier the thousands that have this problem and are told by their local dealer its safe to operate in that condition or the fact that no body is doing anything to assist or fix the problem. Please be the ones who make the difference here..... thank you [xxx] ps I apologize I am writing you again, I never received any response the first time....... information redacted pursuant to the Freedom Of Information Act (FOIA), 5 U.S.C. 552(B)(6).

- Lyndell, PA, USA

Saturday morning I warmed up my car for 5 minutes. Started to drive my car for about 15 seconds, AWD service required popped up on my display. I stopped the car and brought it back home. Looked up what the issue could be and found out that the acd pump has failed. This is a well known problem from Mitsubishi for these cars and they have not issued a recall or real fix. Without the acd pump functioning, there is a possibility that the car can lose traction in certain situations or damage the entire drivetrain system. Mitsubishi claims that its not part of the drivetrain so there is no warranty and it's also a "luxury" system. Controlling wheel traction is not a luxury its a safety feature.

- Chicago, IL, USA

Mitsubishi motors of America has a AWD ECU software update for vehicles specifically driven in cold conditions. Dealerships and Mitsubishi corporate have denied my claim to obtain this software because my car was sold in California and they have said it is not eligible. I take my vehicle every year up in the Sierra Nevada mountain range where temperature conditions are similar to any of the northern states within the service bulletin. The Mitsubishi service bulletin number is SC-09-002 also available here on google docs to read ( docs.google.com/fileview?id=0bznigp9lgbk8ntu5otrinjgtztjhmc00mjy0lwi2nmmtowzhzju1nzfkndcz&hl=en) it states that "this reprogramming procedure will modify the all-wheel-control (awc) ECU software to accurately match the operations check of the ayc/acd motor with current ambient conditions. Extremely cold weather causes increased excessive load on the motor, which could result in damage to the motor. This bulletin describes procedures to reprogram the awc ECU with new software parameters to prevent this condition." The safety concern is that if I'm using my AWD vehicle in cold conditions and the critical AWD components fail due to driving in cold conditions as stated in the service bulletin and cause me to have an accident or even hurting others which can be prevented with a 20 minute software update that is available now.

- Fremont, CA, USA