Alternator Question (yes I searched)

[mikieboy]

Hello Everyone,
I just bought a 2007 XC90 with a 3.2. The power service urgent light was on, so I had a new alternator put on (probably spent too much but I was out of town without tools) After the new alternator was put on the errors stayed the most it will charge is 13.5 v not 14. I did drive all the way from NJ to Alabama and it was fine however I would like to fix the problem not just pray the entire the time. They put a 180 amp alternator on not dealer but indy shop.the number on the back is 0125811051 looking online I have seen some post the part number is 0121715009 is there a differrence? Before I found this out I thought it could be the ECM not telling it what voltage to charge so I sent it to xemodex and it tested fine they at least gave me most of the money back (yes I shouldnt have thrown money way lesson learned) I have ordered a dice connector but its coming from China so I have to wait a bit. Any thoughts on where I should go next? I saw FCP has an alternator should I get one of those or a new voltage regulator. Any help would be greatly appreciated, The dealer is over 2 hours away but I may need to head that way. Thanks in advance.

[Oly850]

I didn’t know that these regulators are externally regulated, so you probably got one on the new alternator, and it’s not that. I think it’s worth a phone call to IPD or FCP with the p/n on your replacement alternator to make sure it meets spec with whatever Bosch unit you are replacing it with. Volvos have very specific battery, bulb & alternator requirements and in 35 years of wrenching I’ve never got around any of them to save a few bucks.

[chitownV]

13.5 is normal as long as it can maintain the voltage with the vehicle’s electrical load. If you don’t experience any issues, it isn’t a problem.

The problem would be if the shop changed the alternator, but kept the old decoupler/clutch from the alternator or if the gear/pulley on the engine side has a loose bolt.

[ggleavitt]

Think you'll find the magic number is 13.8VDC as the "unmanaged" default output, a small distinction and one shared by the V8. Put a nominal load on (3.2 is a 180A?) and it's probably 13.5VDC. As Oly850 notes above, these alternators use a direct LIN data connection to the Denso ECM for determining output voltage. OP, maybe see if you're reporting an ECM-P062001 (P0620?) as part of your troubleshooting, that should tell you definitively if you have a control line issue from the ECM's perspective.

[chitownV]

Yup, measuring via OBDII while driving in my own 3.2…personally I see 13.5V which is normal, like I originally said, .

Again, the real (relevant) alternator related thing to check for in the 3.2 specifically is if the shop only changed a bare alternator (no decoupler) or if they changed entire unit assembly (with new decoupler). The reason is this wears out over time and can stay fixed. These are designed to free wheel when letting off the throttle, so the alternator does not spin down fast with the engine. This should be double checked. The 3.2 likes to rev its engine, thus it’s important.

[ggleavitt]

Would be interesting to see if any of these codes are being produced after visually inspecting the mechanical.

ECM-P062001 Generator Control Circuit. General Failure Information. General electrical failure, B6324S
ECM-P06204B Generator Control Circuit. System Internal Failures. Over temperature, B6324S
ECM-P062074 Generator Control Circuit. Mechanical Failures. Actuator slipping, B6324S

[chitownV]

visually inspecting the mechanical.

Could you quickly enlighten us of what to visually inspect?

[ggleavitt]

@ChitownV, I'm just trying to being respectful of your last comment as you seemed to suggest that the alternator was perhaps not spinning properly. I'll guess that you can shine a light at the back side of the alternator to identify movement on the stator or put your hand on the alternator body to feel movement but I think the OP has already stated that the charging system is producing a nominal 13.5VDC so something in the alternator must be working for that to occur.

B6324 Generator 180A.JPG (40.78 KiB) Viewed 1362 times

I would still go to the codes before making too many assumptions.

As a side note, VIDA has a very good write-up on the charging system, worth a read to get a better handle on how this works:

The central electronic module (CEM) has built-in functions for regulating voltage level and current consumption in the vehicle. The central electronic module (CEM) controls the charge regulator either directly or via the engine control module (ECM). In this manner, it also controls the current/voltage produced by the alternator.
The generator does not initially charge when the engine is started. The charge increases successively when the engine has been started. When there is an increase in load at the generator, the increase from 0 – 100% takes place over the course of a few seconds (this time varies slightly depending on the operating mode the engine management system is in). This is to gradually increase the load on the engine during the start-up phase and to ensure the engine starts.
If the engine speed (RPM) exceeds idle speed (the exact engine speed varies slightly depending on the mode the engine management system is in) during this delay, or if the progressive increase is interrupted, full charge is obtained immediately.
If there is no communication with the charge regulator, the charge regulator will not start charging on start-up. The charge regulator can however self magnetize the rotor and start charging. This occurs at engine speeds greater than approximately 2100 rpm. There is no charge engagement by stages with self magnetization, the generator operates at full charge immediately.
When self magnetizing has begun, the generator (GEN) also charges at engine speeds below 2100 rpm.

As to freewheel- no rocket science there, it's just to prevent belt transmission jerking (also in VIDA). The 3.2 I6 has a freewheel, the V8 does not.

edit 012723- belt [transmission] to match the VIDA verbiage.

[chitownV]

So, you don’t have any experience in what to observe visually mechanically? I am truly asking in case you had any experience different than me and other 3.2 owners.

For those of us with experience, we know it is difficult to get to the alternator without removing the intake manifold. You can get a phone underneath to take a pic of the part numbers and zoom in on the belt, but that’s pretty much it. Don’t know what else “mechanical” you can visually check. If it’s yielding proper voltage, it’s visually there.

I have already mentioned regarding the alternator,
1. Finding out about the decoupler, which could be from the work order paperwork or the shop.
1.5 If the decoupler was swapped, if it was tightened properly as it’s a reverse thread.
2. Perhaps the well known loose gear/pulley bolt on the Read side (needs thread locker). This could have caused the initial charging issue and may not be a problem until the rpm’s spin up, thus…
3. Like I mentioned, if the voltage is maintaining…
4. I also mention I get the 13.5v while driving, varying the rpms

Instead of visually looking, one can try to reach for the gear/pulley on the Read side and see if it is loose, using your hand (not eyes) to check for looseness, which might indicate a loose bolt, it might not.

These are all from specific 3.2 experience and specific 3.2 owners’ feedback….of which could trigger codes. This is a good example of the value in specific real world hands on experience. This is why we prefer to use shops with hands on Volvo experience because this shop could have missed these little (alternator) things in the repair.

[ggleavitt]

Uh okay, so you were not satisfied to the answer I gave to your question. Seems as though you're pretty confident about the mechanical angle, I'll defer to your assumption while still suggesting that the OP check codes to see what the vehicle thinks is going on.

Nothing unique about the 3.2 charging system, other than the way the alternator is being driven it's fundamentally the same as the V8.