Advice from Auto Electrical Guru's

[georgehifi]

Hi, I have a Mitsubishi A3TB1891 alternator on my H6 2003 gen2 vcd Outback. I thought the battery died because I measured 10.5v and then 13.8 started, so I assumed the charging was ok, I was wrong.
When I got a new battery it started fine but the abs vdc lights came on, I stopped the car put my meter back on the new battery it was 12.7v then started the car it was 13.8 with the abs and vdc lights on. Then after a 30 seconds the volts droped to 12.7 again, so I turned on the head lights and the volts shot up to 14.3v. Turn off the head lights it goes back to 12.7.
So the alternator sort of works (over voltage) when it sees the load of the headlights, and when there's only the new battery it stops working??? Is this diodes or regulator?
Thanks George

[grossgary]

make sure the connections/connector at the alternator are clean and solid. most likely they are. otherwise the alternator sounds like it is dying. i would replace it immediately if it's flopping between low and high voltage like that.

if you've never addressed the two serpentine belt pulley bearings, now would be a good time to replace those as well. $10 in parts and only a couple minutes once the alternator is removed. there's a sticky about that issue, i consider it routine maintenance on H6's. buddy just bought one with only 100k on it and i got right into those pulleys - one had obviously been replaced before and the bearings were not great already. i replaced them.

$55 shipped and i can send you a used alternator off a 2002 H6 VDC OBW.

[georgehifi]

Just saw a well regarded auto electrician, he said when he first saw this same thing it had him stumped as well years ago, so he talked to Subaru and found out this alternator in this car has what's called a smart charge system.
Where when the car is running and no lights or fans or accessories are on and the battery is in good condition (12v) the charge is off completely and only the battery is supplying the volts for the ignition and computers ect. As soon as the, smallest thing is switch on like the 1st fan speed or parking lights, or brake lights the charging is switched back on. This was why I was getting 12v at idle or revs with accessories all off, and then 14v as soon as something is turned on. BTW the radio alone will not do this.
But my abs and vdc are still on and cannot be cleared with my or his obd reader, he said that he has struck this before and only the proper Subaru obd tool may erase it. I will go to Subaru on Monday and see if it does.

Cheers George

[grossgary]

ABS and VDC lights do not go off until the offending issue is fixed. you can not "clear" them like you can a Check Engine light.

fix the problem causing them to light up and the ABS and VDC lights go out on their own immediately. Subaru can read the code for you, or you can ground the pins and read them yourself.

that explanation sounds strange for a few reasons but doesn't really matter either way.

[georgehifi]

Originally Posted by grossgary

fix the problem causing them to light up and the ABS and VDC lights go out on their own immediately. Subaru can read the code for you, or you can ground the pins and read them yourself.

It says in the hand book that the abs and vdc will come on if the car was driven after a jump start with a flat battery which is was, and will continue to remain on till the battery (which is now new) comes up to full charge, which it hopefully is yet to come up to full charge as it was probally sitting on the shop shelf for a few months before it went into my car, fingers crossed.

Cheers George

[georgehifi]

Just found these threads , exactly what I was told, I still hpoe my abs vdc go out when fully charged.

Design fault in the "Smart" voltage regulator - Subaru Forester Owners Forum

http://www.subaruforester.org/vbulle...-issues-93651/

http://forums.nasioc.com/forums/showthread.php?t=208567

Cheers George

[georgehifi]

Lights still have not gone out, and I'm sure the new battery is now charged.
Took it to Subaru they say they got a code 71. I need a new "steering angle sensor" $1028.00 !!!!!!

Cheers George

[bigdadi]

www.car-part.com

[grossgary]

Originally Posted by georgehifi

Lights still have not gone out, and I'm sure the new battery is now charged.
Took it to Subaru they say they got a code 71. I need a new "steering angle sensor" $1028.00 !!!!!!

Cheers George

um, yeah right, that's insane. steering angle sensor shouldn't effect the ABS should it? maybe it does.

i rebuilt a 2002 H6 VDC OBW that had been wrecked. not sure what hte steering angle sensor is - but a used one isn't worth anything because demand is zero - it's not a part i've ever heard of failing/replacing. $50 tops from a junk yard.

i got a complete used set of side impact air bag seats, drivers side, passengers side air bags, air bag controller, etc - for $250 off ebay. separately from the dealer those would have probably been $5,000, which is probably why i got the car so cheap.

[georgehifi]

Just got the steering angle sensor replaced by All-Drive Subaroo, here in Sydney, and yes this is the way they spell it.
They fitted a s/h one and calibrated to the yaw sensor and all is fixed for just $260 total. Or I could have had a new one for $500.
Nori said the photo diodes go in them when weird thing are done with the car electrically/batter/alternator. These guys are great because the Subaru dealer as I said wanted $1100 to do it, "rip-off merchants"
I will one day, open my old faulty one, which are sealed, to see if the photo diode itself can be replaced

Cheers George