Alternator

Tiny
JAMESRBRAD
  • MEMBER
  • 2011 BUICK LA CROSSE
  • 3.6L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 69,000 MILES
I am having a problem with my wife's car where for the last two mornings upon initial startup the car will not start. No noise or clicking. However, the parking lights and dash lights illuminate and the check engine light shows. The afore mentioned lights stay on until I detach the negative terminal cable wait a few seconds then reattach the negative terminal. Unfortunately when I disconnect the battery I lose any possible check engine code. I took it in for a battery check and I have been told that my alternator is generating 14.7 volts and I should replace it before it ruins my battery. They said the favorable range should be between 12.5 and 13.5 volts. Is this accurate? And is it possible that the overcharging has caused an electrical issue in the ignition system?
Wednesday, January 31st, 2018 AT 9:43 AM

7 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good afternoon.

The acceptable range for charging system is 14 to 14.5 volts. 14.7 is a tad high but is not an indicator to replace the alternator.

Did they load test the battery?

Also, do not remove the cable and reattach. It does nothing. If there is any codes they must be documented, diagnosed and necessary repair performed.

Roy
Was this
answer
helpful?
Yes
No
+1
Wednesday, January 31st, 2018 AT 11:13 AM
Tiny
JAMESRBRAD
  • MEMBER
  • 4 POSTS
I am not sure about a load test. The car was running but at an idle at the time they checked the voltage.
And as far as disconnecting and reattaching the negative terminal not doing anything, in my case something must have got reset because once I reattached the cable my car starts right up. Two mornings in a row.
Was this
answer
helpful?
Yes
No
Wednesday, January 31st, 2018 AT 11:33 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Okay, then you have other issues.

Did the check engine light come back on?

Roy
Was this
answer
helpful?
Yes
No
Wednesday, January 31st, 2018 AT 11:44 AM
Tiny
JAMESRBRAD
  • MEMBER
  • 4 POSTS
Not until the next morning when it wouldn't start again.
And I may not have made myself clear but in the morning when I try to start the car and it wont turnover the parking lights and the dashboard come on but wont go out until I disconnect the battery. I waited about 10 minutes just to see and they stayed illuminated.
Was this
answer
helpful?
Yes
No
Wednesday, January 31st, 2018 AT 12:46 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
OK, would love to have the code. Something is locking out the starter relay from working. That is the pcm. It is being told to lock it out. Thats why the code would be very helpful in trying to help

when you pulled the cable the pcm forgot the command. Thats why it started

Roy
Was this
answer
helpful?
Yes
No
Wednesday, January 31st, 2018 AT 1:13 PM
Tiny
JAMESRBRAD
  • MEMBER
  • 4 POSTS
Yep. I took the car to a mechanic a there is no code logged. I left the car so they can try to get the fault tomorrow morning. Thanks.
Was this
answer
helpful?
Yes
No
Wednesday, January 31st, 2018 AT 4:15 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Your welcome. Keep us updated

Roy
Was this
answer
helpful?
Yes
No
Wednesday, January 31st, 2018 AT 11:00 PM

Please login or register to post a reply.

Related Alternator Overcharging Content