Can a bad alternator cause check engine light to flash

Tiny
THEGREATECB
  • MEMBER
  • 2005 CHEVROLET IMPALA
  • 3.8L
  • 6 CYL
  • AUTOMATIC
  • 95,000 MILES
I have had an issue with a weak battery on my car. This time, when I jumped the car and got in to take off, my check engine light now starts flashing and car drives like it is misfiring. Could a bad alternator cause this? It always drove smooth before even after I jumped the battery on previous occasions.
Thursday, March 8th, 2018 AT 6:04 AM

4 Replies

Tiny
PATENTED_REPAIR_PRO
  • MECHANIC
  • 1,853 POSTS
Were the jumper cables accidentally hooked up backwards even for a split second?
If so, you could have blown a diode within the alternator.
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Thursday, March 8th, 2018 AT 7:42 AM
Tiny
THEGREATECB
  • MEMBER
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Possibly. Would my battery light have come on if it was the alternator? Only thing that showed up was the flashing check engine light.
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Thursday, March 8th, 2018 AT 8:00 AM
Tiny
PATENTED_REPAIR_PRO
  • MECHANIC
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Oh, I read that too fast, I read alternator and flashing light and thought battery/charging light.
No, the check engine light flashing and the misfire probably does not mean the alternator. It most likely refers to a engine sensor malfunctioning. What you will have to do is have the engine trouble codes retrieved to find out what that check engine light is referring to. When the check engine light comes on, that means the computer has found something wrong and stored a trouble code. When the check engine light flashes it usually means the problem can be serious. Places like AutoZone, AdvanceAuto usually retrieve engine trouble codes for free. Just do not drive too far without getting the codes retrieved.
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Thursday, March 8th, 2018 AT 8:13 AM
Tiny
RENEE L
  • ADMIN
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Hello THEGREATECB,

If you decide to conduct the code scan yourself here is a link to an informative article from this site. This article features written step by step instructions, pictures and a video on how to conduct the scan.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

You can purchase an inexpensive scan tool from online sites like Amazon.

If you need any further advise please return to this post. We are always happy to help.

Kindest regards,

Renee
Admin
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Thursday, March 8th, 2018 AT 10:26 AM

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