CAN THE PCM MAKE A NEW ALTERNATOR GO BAD?

  • Tiny
  • Gman316
  • 2003 Mazda 6
  • 154,000 miles

I replaced the alternator twice. After I replaced it the first time I had it checked and it was bad. So I replaced it again and the charging system light is still on and the problem is still occuring the same exact way it was before. Also just put a brand new battery in when I replaced this alternator. The problem happened as I was test driving it around the block. So my question is can the PCM cause the alternator to go bad or did I just get another bad alternator or is there some other problem?

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Wednesday, July 11th, 2012 AT 2:39 PM

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  • Tiny
  • Docfixit
  • Expert
  • 18,993 posts

PCM would not normally make ALT fail BUT PCM does regulate ALT output so PCM could keep ALT from working

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Wednesday, July 11th, 2012 AT 2:45 PM
  • Tiny
  • Gman316
  • Member

So should I take it to see if the PCM is bad or just replace the alternator again?

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Wednesday, July 11th, 2012 AT 2:55 PM
  • Tiny
  • Docfixit
  • Expert
  • 18,993 posts

Remove ALT from car have tested if good then PCM at fault or wiring

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Wednesday, July 11th, 2012 AT 2:59 PM

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