'06 S80 alternater - now what?

[tridents65]

Ok, so I took off a bad alternator and had the bearings replaced. Put it back on and it ended up not working right (to long to go in to) But, I did drive it around for awhile so as far a charging it was fine. Today I took it off and replaced it with a remanufacured Altima. Hooked everything back up and stated the car. The battery light came on and a text message that says "Power System Service Urget" Dang! Took the empty box back to the parts store, "will you look this up again and tell me I have the right amps". It should be a 140 amp. I determined this by giving mt vin code to both an internet supplyer and a dealer. Both said it's a 140. Ok, so the parts guy said, "it's a 140". Ok, Drove the car around for awhile. Checked the battery, it's at full charge. Used a volmeter at the battery with the car running the alt. is charging at the right amps.
So what could this be? I did not get any of this when I took off the old alt and put it back on, so I'm a little confused. Is it some kind of code that has triped because I installed a different alternator?

[regent]

How much are you reading w/engine off and w/engine on? At idle, read at the gen positive and at batt positive; how much is the difference? Is there a change in the system voltage when you rev vs. idle rpm?
On another note, your generator drive pulley has the same diameter as the original one, correct?

(Lastly, when the bearings fail, the collector rings and brushes are already pretty worn out, too.)

The answers to the above should narrow the fault down to wiring or to the gen/voltage regulator itself, yes?

[tridents65]

I put the same belt back on since I had just changed it so that will be the same. I will do the other suggestions you made in the next couple of days (don't need to drive it now) since it is getting late (dark) now. What am I checking with the engine off? Would the Generator warning light come on it the alternator is over charging because of a bad regulator?

[jimmy57]

The alternators on 2005 and later must have an integrated voltage regulator that has communication capability . The new style VR is called an alternator control module, ACM. The CEM inside the car adjusts the target charging voltage based on some measured and computed parameters and instructs the ACM of the target. I would bet that the replacement has a conventional voltage regulator that would be perfect for a 99-2004 but is not correct for 2005 and later. IF their catalogs show the same part number for 04 and older and 05 and newer then it is not the proper one. It will charge fine but the message will be there due to the communication missing to the CEM.

[regent]

That's right, and if VR is offline, then a Comm Fault code will be set.
When the VR is doing its job (target voltage is met and communication with network is OK), the problem and resulting message will be due to a wiring issue such as corroded or loose connections along the 'positive' loop (between Batt+ and Gen+ points) or in the 'negative' loop (ground straps.)

The voltage checks suggested earlier would help assess that quickly.

[tridents65]

Spent some time on the phone today with O'Reily Auto Parts, The company that remanufactures the alternator, and a couple of internet suppliers. Turns out that O'Reilys' parts catalog is wrong showing the same alt for '04's and '06 just as jimmy57 suggested. In speaking with the reman. company, they don't rebuilt the correct alt for the '06 yet. I bought the right OEM Bosh (rebuilt) alternator from FCP. The Bosh number for those interested is AL0854X. Price was 280.00 + core and free shipping. I have purchased from FCP in the past with no problems. Should have gone there first. Was trying to save a buck. Lesson learned (the hard way; still have to pull the O'reily alternator off to put on the Bosh).

[regent]

Glad you've caught your Gremlins!
Thanks for sharing - we all benefit by learning from each other.