Alternator Dead at 94k ?

[MacKay]

2009 G8 GT - All stock - 94,000 miles.

Yesterday, alternator warning symbol on DIC....comes and goes. Left work with engineering mode on shows battery charge around 80%. After driving 5 miles, it was down to 60%. Battery saver mode then came on.
I replaced the battery 1 year ago.
Drove to dealer this morning...no more alternator warning...and the charge now says 83% ?? So the alternator was working this morning ? Weird... but now the Check Engine light is on.
Dealer calls and says the alternator needs to be replaced....parts and labor $ 710.00 -- OUCH !! Does that sound right ???...$710.00 for an alternator ?
Dealer says Check Engine light is related to low oil pressure....details to follow.. all this in one day ?.. related somehow ??
And my tire pressure monitoring system died 5 months ago...DIC just says Tire pressure system failure...

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Interesting update !...
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Dealer called me late afternoon and said the alternator replacement was complete. Said his mechanic couldn't check the engine code related to the oil pressure or pump until tomorrow (it was too late in the day). But I was promised my car would be completed that day, and I needed it that night. The service technician told me if I picked it up , I could risk blowing my engine. I asked him if the new alternator had cleared the code and he said NO. I decided to pick it up anyway....they pulled my car into the pickup area...and guess what...No more check engine light and my tire pressure system is now working fine on all 4 tires !! I called him over and he still insisted the code was there....so why is there no check engine light I asked? He then plugs his diagnostics tool under the driver's dash to prove it to me....but nope...no codes ! I knew they never checked for codes after the alternator install....and he couldn't come up with any answers.
With the new alternator, in engineering mode, the battery charge level is staying at 11.3%....that sounds low to me....and after driving several miles it doesn't change... I really don't understand what that "Battery Charge" percentage means..... Yesterday ( with the bad alternator ), it was at 80%, then 60%, then battery save mode....
Ideas anyone ????

Update #2 - Started in engineering mode the next morning. Battery Charge level now shows 95%. I guess everything is good now ?!

[texn884]

Ouch is right but did you see where that thing is mounted?
Better than a engine take a shit at 98,000 miles like mine did but I got a new engine casue it was still under warranty

[Napalm]

so the alternator cost is 1/2 the install. Part is something like 300 or so. Check rock auto - price the actual AC delco one. Also don't get a non AC delco one. Really DO NOT.

They are a touch unique to this car and the way they are modulated. There are something like 3 part numbers that work right with the G8 - one is the orginal, one is off the PPV and the other is off a specific year truck. IIRC.

Replacement isn't that difficult however so maybe tackle that yourself - if you're up to it. Any non dealer shop can do it and save you a ducket or 2.


ON the oil pressure - honestly I'd fix the alternator issue - and get the power system stable - reset the computer. AND then check the oil pressure issue. As it might just go away.


Tire sensors - I have the same problem and while I know people swear those TPMS sensor are "supposed to be guaranteed for 10 years . . . . . " I've not once seen one that was warrantied beyond 3 years. Your issue is one of your sensors died - if you go into engineering mode and look up tire pressure I bet one of them reads 148.

you have an 8 year old or more car - that came to you buy ocean ship - now is about the time it needs a little TLC. Mine does too.

[MacKay]

Thanks for the advice Napalm.... I checked the tire pressure readings in engineering mode....all four read 148....hmmmm

[JimmyJazz]

Here's one of the greatest threads ever! Takes about two hours. Like Napalm said, Delco alt only! Bought mine from Amazon. http://www.g8board.com/forums/9-ster...placement.html

[Napalm]

well I retract what I said then - if all 4 or showing 148 then it's possible it's is the TPMS controller. It is still possible all 4 died though.


Issue you might have - do you drive the car often or does it sit for extended periods of time? what is the temp range whee you are - currently.

TPMS sensor has a small battery - or in some cases a SuperCAP - and if the tires don't run for a while - it will die. They get recharged by the rotation of the tires. Not they should last for some period - but long times with no charging - and cold temps - kill them faster. And as such you could kill all 4.

If you checked engineering mode with the car parked - and it's not moved for a while - maybe drive it out for a bit - and then check to see if all 4 still say the same.


Finally - go though the sensor re-learn cycle. It's what tire shops have to do when you rotate the tires. I forget the procedure but it's in the book - requires some button combination - and then the horn honks - you let out 4 or more PSI and put it back on the LH-front tire - honks again - move tires - repeat 4 times - get a tripple honk. COurse if that first sensor is actually dead - it won't continue the process as it never sees the pressure change. So try other tires out of sequence if you want to.

[MacKay]

I updated my original post.... got the new alternator and bingo...no check engine light, and my TPS is working fine now....just weird !

[Napalm]

voltage differentials do that. if the computers don't have stable voltage - some of the solid state relays they control won't close, or some of their memory sets won't re-write, etc etc.

It's why on newer cars I tell people to check your fuses - and system voltage first before doing other trouble shooting.