I have a 1996 SVX with a little over 61000 miles, very-well cared for. Starting with a check-engine-light failure after 3-1/2 years, the Subaru dealer has replaced the ECU 8 times and has the 9th replacement on order (the most recent unit endured for 17 miles, a new record)! In every instance, they have been unable to pull the trouble code from the computer. I am told that they and all levels of Subaru (including those at Fuji) have tried or considered everything and have no idea what is causing the problem. They believe that something is shorting-out the ECUs. Almost 3 years ago, they replaced all 3 wiring harnesses and the alternator (which was spiking, apparently). All to no avail. Except for the alternator and a new battery, all this has been at no expense to me, thankfully.

The car's operation has not been affected, at least not until recently: I have some skipping during idle, especially until the car has run for quite a while, after which it smooths-out (relatively speaking). They claim that is related to the computer failure; however, I am not sure about that because it has never happened before and continued during recent brief stretches when the check-engine-light extinguished for a couple of days. All the plugs were replaced by them a little over 1000 miles ago.

By the way, the light has gone off 5 different times during the 2 months since the last failure, always at start-up, and remains off for varying lengths of time and mileage - none very long.

The dealer says that Subaru has never experienced this kind of failure and is now apparently content to continue to replace the ECUs. I have periodically searched SVX chat sites and although there are many check-engine-light stories and solutions (usually involving the oxygen sensor), I have never found one such as mine.