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2008 Subaru Legacy Manual Transmission engine shut down while driving!


I could really use some help with this one ASAP as the car is with the dealer and I am not convinced they are addressing the problem. A few days ago the 7 month old car shut down as we were driving 70 mph on the high way. Pulled off to side and car would not restart, would not even try to turn over. Towed to dealer who said computer showed battery cells were low which caused the computer to shut the engine down?? They replaced battery and reset codes and off I drove. Two minutes after leaving the dealer the same thing happened on the highway !!! Back at the dealer again. Has anyone heard of this being a problem with Subaru’s from 2008? The car has 9K miles and this is really stressing me out. Any ideas?

What is there to get stressed out about? Put it in perspective: people are dying in the war in Iraq. All cars have problems, even 2008 Mercedes Benz’ with $100,000 price tags. If the shop can’t fix your problem, contact Subaru of America and explain your situation. Look on the bright side, if they have it in the shop one more time for the same problem, Subaru can buy it back from you!

Ok, now I’ll try to post an answer that’s actually helpful.

I’m not sure about that dealer’s diagnosis…a 7 month old battery should not be low in the first place, and I have NEVER heard of a computer commanding engine shutdown because the battery was supposedly discharged. This sounds like a line of BS. Personally, I’d recommend a different dealer.

Not sure how helpful that actually was, but hopefully it gives you something to think about.

Hey Budd - My 2001 BMW 750il will go into limp home mode if the battery voltage is too low. Try again.

Well lets say the computer did store a code for low battery voltage, The first thing to look at is the battery, followed by the alternater. Checking the connections to be sure they are clean and tight. then procceding to check the belt and to verifiy the car is charging at low and high rpms. If all is well with both I’d lean to a bad body control module, or powertrain control module. When your car died either time was the battery dead? Did the hazzard lights work, or any other power option? Rest assured the dealership is doing what they can. The warranty work is out of their pocket (so to speak) not yours, they don’t want the car there anymore then you do.

Some more info always helps of course. It would be helpful to know what codes were stored and when the car failed to start did the dashboard warning lights illuminate?

If everything was dead with no dashboard lighting then my guesses (and wild ones at this point) would be a main fusible link problem; not plugged in all the way, wire connector for the link partially unlocked, or even the errant possibility there is an ignition switch problem.
Yet another could be a security system glitch if the car has one.

To expand on what alex said, he is referring to the Lemon Law. At this point, I would suggest that you begin familiarizing yourself with the details of that statute in your particular state. Although they vary in detail from one state to another, these laws all require a settlement if the car cannot be fixed after a specific number of attempts by the dealership, or if the car has been out of service for more than a specific number of days.

Every car manufacturer produces a few lemons, and it is possible that you have gotten one. It is also possible that this is a problem that will be fixed on the second try. But, “forewarned is forearmed”, so if you know your rights under the Lemon Law in your state, you will be prepared to file a claim at the appropriate time if the problem cannot be rectified. The statute in some states calls for a free comparable replacement vehicle, and in other cases, it calls for a refund of your money.

So–be sure that you retain documentation of your service invoices stating the nature of the problem, and keep track of the number of repair attempts and the number of days that the car has been in the shop. This way, if the dealership continues to be unable to repair the problem, you will be able to take action as soon as it is appropriate.

Good luck!


they say it is a relay switch that they are replacing. Given that this is the second try I assume they re certain that this is causing the engine shut down.

Along with some of the other posters I too think there is a connection problem in either the main connection between the battery and the main panel under the hood or the power lead to the ignition switch. While this kind of thing can be a real show stopper it isn’t a real bad thing like running the engine without oil in it and should be pretty easy to find if they can make it happen while in the shop. Intermittent problems can be hard to trace at times. By tapping on suspected areas with a screwdriver handle it may show up the trouble.

I assume that the replacement battery was charged up fully and it was new. This would eliminate the battery as the source of trouble. I don’t know where the shop measured the battery voltage for sure but it sounds like it was taken from the OBD2 test plug. Having a connection problem in the main power buss wire from the battery would cause a voltage drop across the bad connection and then make you think that the battery was low; since the bad connection is ahead of the test point; but it really could be fully charged. It would really help to know if anything worked while the trouble is occurring to help pin down the trouble area. If the shop has a good savy electrical troubleshooter he will track this pretty simple problem down fast. If he can duplicate the problem at least.

I am sorry to hear this happened to your new Soob and try not to worry about this. You should be in for a lot of trouble free miles after this is fixed. They are great cars I think and have a LL Bean myself. My two sons have Outbacks also, and they are all the same color. The neighbors probably think we are nuts but we don’t have any car troubles, not that it can’t happen though.

Keep us posted on the progress. If the shop can’t find the trouble the folks here will get you going if they can’t. There are some real savy techs looking for trouble on this board. You may want to check out the USMB board also.


I see some new info came in while I was writing this. The relay is a very logical item to replace and could be the cause of the trouble alright. Hopefully they were able to prove it was the problem rather than just gussing it was.

It sounds like I have the same problem. My '08 Legacy w/ automatic died yesterday. It was a silent and instant death. Luckily, I wasn’t on the highway. It won’t turnover but all lights and stereo work. The ODO shows an error message reading ER HC. The dealer is clueless about what that means. My net research suggests it’s the “highspeed con” (highspeed computer)which controls the engine and transmission. My car is 9mos. old with 8900miles. The dealer has had the car 2 days and they have no idea what to make of it.

Well, there are LOTS of relays on modern cars, so unless you know which relay they think is causing the problem this doesn’t really mean much.

Proof that automotive technology changes faster than the dealers can keep up with it. Be glad you don’t own something even more complex.

Sounds like a bad dealer.

Do you have anything aftermarket installed (good reason not to)

This same thing just happened to my 2009 Subaru Legacy automatic with 14,000 miles. Did they fix your car? What was the problem?

I’m currently having the same issue with my '09 Legacy automatic w/ 42k miles. The engine shut down on the highway at about 60-70mph… The dealership that I brought it to can’t figure out the problem because the car now starts up ok and they say it drives fine and there is nothing wrong with the car. I’m a little concerned that if I take it back I will have the same issue.

A little background info… I had an oil change, differential fluid change done on the car the day the issue came up.

I’ve contacted Subaru of America to have them look into the problem because I don’t trust the dealer. I don’t feel as though I’m getting the same level of service I would have had I bought the car from them. Frustrating all around!