Hi,hope someone can shed some light on my problem.Had my '04 wagon(PPP) for three months with no problems.One day I tried to start it and had no battery charge,got it jumped and went for a little run to try to charge it up.Next day,same problem,jumped it and took it to my local garage.They said the battery cells were fine but the alternator wasn't charging it.Changed the alternator and had the malfunction indicator,battery warning and brake system warning lights come on and stay on.Never had these lights remain on prior to this.Changed the alternator a further 2 times with same results though when driving it,the battery and brake warning lights do go out for a bit.My garage are scratching their heads and think it may be the ECU(they don't have the diagnostic software) and then took it to a Subaru garage(MKG3000) and they said it was the alternator.My questions are-does it have to be a Subaru recommended alternator for the car/ECU to recognize it and would there have been a chance that the ECU got spiked when jumping it?Any help would be great,thanks guys...

 

Your car has a "smart" alternator. There is a 2 and 3 wire version, i would guess the garage has fitted the wrong one confusing the ECU.

Plenty of threads on the smart alternator, have a search, you might even find there is nothing wrong with your old alternator, especially if the garage didn't know it required a load (amp draw) to excite it.

 

Thanks for the reply,omitted that they knew it was a 'smart' alternator,don't know about the 2/3 wire versions though or the load.How sensitive is the ECU to an incorrect alternator?Thanks again and will check other threads..