Alternator 2.5L Turbo vs N/A

I've had some charging issues over the past 1.5-2 yrs and think my alternator is to blame. It always tested ok but over heated two different batteries. I bought a spare to rebuild and install but found some interesting stuff when getting parts to rebuild it.

 

My 2005 LGT has what I always believed to be the original alternator. So the replacement I bought was the same one: Mitsubishi A003TG2391ZC. That part number brings up 2005-2009 Legacy 2.5L non-turbo.

 

In the fsm, the 2.5L turbo uses Mitsubishi A003TG0491.

Here's the real mind boggler: According to the FSM, both alternators are the same rated Amperage and output the same as well.

What's the actual difference?

Anyone else have a 2005 LGT that can check out which alternator they have?

Damn, dropped mine off at the dealership for the air bag recall.

 

I'm sure someone will chime in soon with a picture of the tag.

 

I wouldn't be surprised if they are all the same just different manufactures.

 

Notice they all seem to be 110amp,

 

https://www.partsgeek.com/catalog/2005/subaru/legacy/engine_electrical/alternator.html

Edited May 5, 2020 by Max Capacity

That's what confuses me. They are 110A and output the same for all 2.5L Legacies, N/A or Turbo. I know it physically fits since I've had it on my car for 10ish years. In my digging there may be a difference in how the connector is clocked (11 o'clock vs 10 o'clock) and the physical depth between mounting ears (79 vs 81mm).

maybe the voltage regulator is bad?

maybe the voltage regulator is bad?

That or the rectifier. I plan on replacing the two bearings, voltage regulator and rectifier.

I still run the one that came with the car. Sticker reads:

 

23700 AA55A

A3TG2391ZC

 

Never had any issues with power but recently the battery holder got all covered by white powder that I believe is acid from the battery (Interstate). Can the alternator be overcharging the battery causing this?

I reached out to Maniac Electric since that is who I'll be purchasing a rebuild kit from and they gave the definitive answer. Extremely fast response too!

 

"Basically the A003TG0491 on the car has a Lamp Circuit Activated Regulator with 3 terminals 'Dummy (no Function)' - 'Sense'* - 'Light'*

and

The A003TG2391ZC has a Stator Activated Regulator with 3 terminals 'Comm' - 'Sense' - 'Light'

most American Market Subaru's only use the 'Sense' - 'Light' (2 wires) even when using a regulator that comes with 'Comm' feature.

You will see that feature used in European Market Subs."

what does it mean for us? What does "Comm" do for alternator? I thought I understood electrical circuits enough to be dangerous but here I am at a loss.

I believe the Comm is a communications line for the ecu. Certain vehicles control charging via the ecu but ours do not.

I believe the Comm is a communications line for the ecu. Certain vehicles control charging via the ecu but ours do not.

what does it mean for us? What does "Comm" do for alternator? I thought I understood electrical circuits enough to be dangerous but here I am at a loss.

Just to add, after looking at the FSM, the 3 wires breakdown is:

WR-To power supply

BW-To charge light

BR-To ECU pin A22 (H6 Engine Only)

So our cars don't utilize the 3rd wire even though it is in our wiring harness.

Just to add, after looking at the FSM, the 3 wires breakdown is:

WR-To power supply

BW-To charge light

BR-To ECU pin A22 (H6 Engine Only)

So our cars don't utilize the 3rd wire even though it is in our wiring harness.

 

 

I think I understand now, this is a-la BMW when ECU controls how much charge goes to battery. Interesting that H6 has it?