Subaru Service Program WVU-31
I wanted to pass along some information that will affect a large number of vehicles, 5 years worth actually.
Pretty much every NA (naturally aspirated) 4 cylinder model from 2006 to 2010. Essentially the front air fuel sensor is not correctly reaching operational temperature early enough in the start up cycle and until it does the content of the emissions coming out of the tailpipe will be increased over the design. I do think its great when something that affects our air quality is recognized and dealt with properly such as this.
2006-10MY Legacy, Outback, Impreza & Forester
Subaru of America, Inc. has initiated a Service Program to reprogram the Engine Control Module
on certain 2006 – 2010 MY Legacy, Outback, Impreza & Forester vehicles with 2.5 Liter normally
aspirated engines. Models with 6 cylinder or turbo charged engines are NOT affected.
A modification to the ECM software logic has been developed to improve the performance of the
emission control system. This software change will not adversely affect fuel economy or
performance.
This software update is intended to improve vehicle emissions when the vehicle is operated in
cold weather and the engine is turned off and restarted within short periods of time such as in
several minute intervals. The A/F sensor contains a heating element, which is controlled by the
ECM, and which assists the sensor in reaching an optimum temperature, resulting in better
accuracy. When the vehicle is operated under the conditions described above, there could be a
longer than desired delay in the ECM’s turning on the A/F sensor heating element, resulting in
higher than desired emissions. This software enhancement will correct that condition.
ECM reprogramming PAK files will not be available for all models at the time this Service
Program is initially released. PAK files will be available in accordance with the schedule found on
page 4 of the WVU-31 bulletin.
Now because the service campaign will affect a huge number of vehicles Subaru is going to trickle out the letters to Subaru Owners, however if you are taking a vehicle affected in for service you should inquire about having it done to avoid having t make a second appointment when your letter comes.
Thanks for reading
Justin
I just had the service performed here in So Cal on a 2008 outback, there seems to be a problem with the idle speed now, wants to almost stall at very low speeds, forward and reverse, any one else seeing that problem?
It is very common to have a 2005 and newer Subaru that struggles to relearn some of the base idle speed settings and some of the Maps as well. It will get better with driving it in varied conditions.
Justin
Yesterday I talked to the service manager about my problem following wvu31 reprogramming (see my earlier post). He told me the engine control module needed to “relearn” some things and that it should get better with driving. He asked me to give it a week and then call back if it hadn’t straightened out by then. If not, they would then clean the throttle body and this should fix it.
I was about to say “What moron would believe a crock of sh_t like this – let’s just schedule the throttle body cleaning ASAP”. But I held back because I figured if there was any chance of restoring my car to proper functioning I needed this guy’s help – maybe lots of it so I just said “OK”. But after I got off the phone I went straight to the calendar on the kitchen wall and penciled in a reminder to call this guy next week.
Bored yet? Here’s the interesting part. Today, I started it up and it drove fine – just like my old car had returned – but it lasted less than 5 minutes. It seems that a cold engine idles at higher RPM and this “fixed” the problem until it warmed up. But as I continued to drive, the problem comes and goes. And now it’s normal most of the time. IT’S LEARNING!!!!!
I just bought a 2008 Forester Sport with less than 10k miles on it from dealership. It stalled at the first stop sign on my way to work the next day. Did it again two weeks later (both mornings were below freezing). The service dept told me they had done the wvu-31 reprogramming and I needed to wait for it to “relearn”. I too thought this sounded crazy until I saw your post.
Please tell me that the problem eventually did go away completely.
I had the software update done on my 2008 Outback and 2 key cycles, ~20 miles later, the check engine light came on. I immediately returned to the dealer and the code was a p0420. The dealer and Subaru both contend there is no way the ECM software update could cause this code. They cleared the warning light, but it came back on about 40 miles later. I took it to my local mechanic and it was the p0420 code again. It just seems way too coincidental. Any thoughts?
http://allwheeldriveauto.com/subaru-check-engine-light-and-code-p0420-explained/
So, at first I took your response to mean that you didn’t think it the reflash and the code were connected. However, in the comments of the P0420 post there is talk of reflashing the ECM. Would you recommend a reflash before tackling the other possibilities?
I had the same recall work done in July 2011. the vehicle had been running perfectly prior to that. Since then the vehicle has been back int he shop 8 times for the check engine light. Several emission parts have been replaced since the service manager claimed it is just a coincidence that they all failed immediately after the reprogramming for the recall and the car is now just over warranty. I am pretty well convinced that none of those parts were faulty and it is all linked to the recall work that was done.
i was just reading Ted’s post, and thought i should mention that my dad brought in his 2006 subaru outback for this update, and the very next day the car would stall repeatedly and idle very rough. the dealer told us they cleaned the throttle body and everything has been good since. 200,000 miles now, and plenty more to come! its my dads 4th outback, subaru’s are the best.
p.s. great website!
Depending on the Dealer, if they don’t do a good job of maintaining the proper level of Battery voltage while performing the reflash The reflash will not go smoothly, this is why in a few cases there are issues, not every Subaru dealer will have made the rather large in vestment into a voltage maintaining device as they can cost over 2500.00.
Next when starting the vehicle for the first time after a reflash if the Tech is in a hurry and doesn’t allow the relays to cycle it will also cause an issue as well.
Lastly not performing a drive cycle afterwards because of the FLAT RATE PAY system at a Subaru Dealership also creates a situation where the owner is given a vehicle back that should have been put though some paces prior to releasing it back to the Driver.
I had the WVU-31 recall completed on July 10, 2011 when my 2009 Forester had about 59,200km. Up to that point the vehicle had been great with no problems. A day after the reprogramming of the ECM I got a Check Engine Light warning. The dealer checked the code and recommended replacing the front O2 sensor (code po137). I replaced it. Shortly after the Check Engine Light came on again. It actually comes on periodically and then shuts off again too. I took it back to the dealer. Now the error code is P2029 and they recommended replacing the duty solenoid. I replaced it. I asked repeatedly if this had something to do with the recall servicing. They replied no and it was just a coincidence. I don’t think so. The Check Engine Light came on again and it is going back to the shop tomorrow for the 7th time since July. They told me there is no way the ECM reprogramming could have been done incorrectly. They said the car would not run if it was done incorrectly. Is this true? And is it likely that the recall work has triggered this string of Check Engine Light failures?
I am sorry your having issues with your Subaru. I have made attempts to try and explain why this can occur but its difficult to explain.
But here is the issue, a computer receives new logic or a re flash which changes some of the parameters of which the computer or (ecm) may trigger a fault code for a given system. A sensor that didn’t trigger a fault code based on the current data it omitted back to the ECM may now trigger a fault code because the ECM wants different data now than it did prior to the reflash. I call this the black and white programming the car came with new, the computer also learns and has something called adaptive strategy where it can compensate for data from sensors a bit out of range with the map ( a pathway the computer follows to achieve results based on data received and programming) it has until its satisfied this is the grey area of computing in a modern vehicle and the part that is the hardest to grasp and the hardest to explain.
Its very much the same as having to go sort out new printer drivers for an old printer when updating to Windows 7 from XP and for some older printers there is no support. Subaru cannot anticipate all of the grey areas when re configuring a new map.
While I do understand your frustration, but that is most likely what is going on,. I am sure soon the bugs will be sorted out but you can and should also call Subaru of Canada and make sure they are aware of the issue. I am not very familiar with Subaru of Canada but I can only imagine they work similar to how SOA does.
Its not all that unreasonable to expect that if this becomes a bigger problem Subaru may have to change some of the calibration factors with the new Map another words re think some of the parameters the computer is looking at to trigger codes now that weren’t prior to the reflash. But having said all of that now its also possible that the 02 sensor and the solenoid were working on the edge of specification prior and when the learned data was wiped out there was no more grey area for the ECM to operate in this is something your Forester previously had a 3 year history of.
The fact that it set a P0137 and then 2029 indicates 2 separate issues and that does sometimes happen. I am sure it will all be resolved soon.
Justin
Hi, got the WVU-31 reporgram, now when I use the remote start, the check engine light comes on, brake lights flashes, cruise flashes (and is disabled). Cleared one time at dealer. Ran great tehn when I tried to go into “Pit stop” mode it did the errors again. Could this be one of those that will work itself out? Do I have to keep going back to clear it until then?
The remote start worked fine until the reporgram.
No there is a bug, cant offer what needs to be done only can say that its not normal and I dont think it will sort it self out. I am assuming the remote start is aftermarket?
Justin
I have a 2010 CVT Outback 2.5 and this ECM update killed my MPG. I was averaging 27 MPG on mixed driving. Now I average 22 MPG. I should have bought the V6 engine and gotten better performance at this MPG. I bout the 4 cylinder since it was better on gas.
I think Honda has a lawsuit on their hands for doing this. This also lowers resell value and is totally selling point is better PZEV for the environment. I’m really disappointed in Subaru. They don’t even have a fix for it.
I might have to go to small claims court or start a class action lawsuit.
My 2005 Ford Escape was just totaled by not 1 but 2 deer at 60mph…. Handled the incident extremly well but car is totaled and looking at a used pre-certified Suburu Forester 2.5X LL bean edition. Heard so much about Suburu and love the car-like truck look. On Carfax it shows this update to WVU31 recall on 5/11/11. The car was sold by its original owner who seemed like a service guru due to every three months in the dealer for oil, filter maintenance since inception of this new car, right after the recall was done. Ouch, i don’t like what i’m hearing about computer stuff running my cars systems and stalling.
What to Do!!! Help
Sorry to hear about your Accident.
As far as computers controlling everything, that is the only way modern cars can achieve the current low levels of emissions that the current laws require.
We have performed the reflash here and its not a big deal unless not done with a stable battery. There is also a “tender” that can be purchased for $900.00 to help avoid the problems with the reflash that some have had, I would imagine that the techs at the Subaru dealers are either lazy or the Dealer wont spend the money on the device.
Justin
I just had WVU31 recall fixed on Tuesday, August 14th. It’s Wednesday, August 15th and my car has stalled and then tonight the cruise control light began flashing and my check engine light has come on. The gas/transmission has been squishy and resistant.
I’ve been reading that the car just needs to adjust, but it feels somewhat unsafe and unreliable at present, and at no time was I warned that there could be any side effects of the recall. Do I take the car back in or wait it out? There is definitely a correlation despite my car needing minor service because the car ran perfectly with no issues until this recall. Since I am seeing similar if not exact symptoms from other owners it is definitely a liability on the part of Subaru. I can’t afford spurious repairs! Has anyone had any luck on waiting it out or getting these issues resolved??
Joy and whoever else reads this.
If the Tech doing the reflash does not do it 110% as it should be done, it will have symptoms for a while why the ECM learns an array of data. Some times the Computer wont.
The only thing you can do is wait it out and deal with the symptoms, or take it back to the Dealer and demand they drive it for the next couple of weeks.
Justin
I have been reading about the WVU31 issues. I have been looking a purchasing a used Subaru Forester 2006-2009. Your info indicates that the NA (naturally aspirated) 4 cylinder model from 2006 to 2010 is affected. Is the PZEV not affected! I don’t quite understand the difference between the two. Sounds like the PZEV is not affected by the WVU31, is this correct?
The Vin number is what determines if a vehicle falls under any campaign or recall.
Justin
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