Buzzard8

Can someone help me please?

The original alternator on my Impreza STi Type-UK, first registered 2006, failed and killed the battery in the process. The alternator was replaced with a recon Delco Remy DRA0366 and the battery with a Lucas LP005L. Now the engine management light is on, fault code P0558 "Alternator Circuit Low" reported and the car refuses to charge. With the engine idling, voltage is 12.5v with no electrics switched on and no more than 13.07v with everything turned on - I was expecting 14v or thereabouts. Clearing the fault code and re-starting the car just puts the engine management light back on. The battery light on the dash illuminates with the ignition on and extinguishes when the car is started.

I was thinking of checking the voltages at each of the three wires that connect to the alternator. They are blue (C terminal), yellow (S terminal) and black with white (L terminal) but I don't know what the readings should be with no load and with load.

Any help gratefully accepted!

JDM_Stig

iTrader: (3)

https://forums.nasioc.com/forums/sho....php?t=2186748

Buzzard8

Thanks but I find that thread difficult to follow.

Something I missed out of my initial post - are there any wiring diagrams available anywhere? I've failed to find any despite a lot of searching.

Don Clark

2.5L hawkeye by the alternator part number.

Buzzard8

2.5 litre hawkeye. Engine code EJ25.

Buzzard8

Thank you, Don.

I see the connections to the generator are black/white, yellow and white. My car is black/white, yellow and blue. I'm assuming that's not really significant?

I've also thought about sending a signal up the blue wire to the alternator (i.e. take control of the blue wire away from the ECU) to see if the alternator responds to the signal. Trouble is, I don't know what voltage/waveform is required?

Don Clark

It's a 4 wire alt. Forgot the diagram that shows the blue (L) wire...... from pin3 of the plug.

why it's not included on the other diagrams I've no idea
White is the main output from Stud terminal.

joz8968

iTrader: (13)

FTR, a healthy alternator should put out around 14.5V

Buzzard8

Thank you for all of the help I've been offered so far, I really am appreciative.

I suppose my questions are - is there an easy way to test if a signal is coming along the blue wire into the alternator, therefore telling it to charge at its full 14.5v, when the electrical system is under load? Or is there a way to send a signal down the blue wire telling the alternator to charge at 14.5v and see if the alternator reacts accordingly?

Or am I now out of my depth and I need an auto electrician?

JDM_Stig

iTrader: (3)

http://strongforsubaru.com/subaru-alternator-fault-fix/

Buzzard8

Seen that previously but thanks anyway. There is load at the ECU, so fooling it into thinking there's a load is pointless.

Don Clark

The MY06 ECU pinout list doesn't show(B136) C10 connection for the generator but the 04 and 05 ECU pinouts do.
Hopefully signal will be the same (although a different terminal)


The DTC's for the generator aren't that exciting

DTC P2503 CHARGING SYSTEM VOLTAGE LOW

DTC P2504 CHARGING SYSTEM VOLTAGE HIGH

MY06/7 Generator info

Buzzard8

Thank you, Don, for all of your help.

I'll run some tests on the car once I'm back from holiday and hopefully I'll be able to get it running (or pass the information on to someone more qualified to help me).

johned

Good luck.

badbaz

iTrader: (17)

check the alternator is earthed, had this on mine before

Buzzard8

*** UPDATE ***

In the end, I took my car to the local garage that supplied the recon Delco Remy DRA0366 alternator so they could test it. They've got a lot of experience and a lot of diagnostic equipment, far more than I could hope to muster. The alternator turned out to be faulty so I left the car with them to sort out. The alternator has been replaced with another identical one under warranty and that's been fine - for a week, although I was told the charging voltage when the replacement one was fitted still didn't get over 13.2v which isn't high enough is it? They kept the car for the week the alternator has been fitted to check it wasn't going to fault again. It's only been moved from one bay or the forecourt to another bay and then moved into a bay for safe keeping overnight, so it hasn't had any proper use.

As of this morning, the car is faulting again with "P0558 - Alternator circuit low" so I've left it with them to check the wiring and the alternator. I'm assuming the alternator will show as being faulty again but could it be something to do with the battery as it's probably reasonable to assume that could be quite depleted by now but I haven't been told that it is or isn't.

Could the state of charge of the battery be a cause for the "P0558 - Alternator circuit low" error re-appearing? Or does anyone have any other ideas please about fixing the car?

johned

Have you tried running with the lights on.

Buzzard8

Running with the lights on doesn't change anything. The P0558 fault logs itself at start-up.

Don Clark

Didn't see the P0558 in your first post but it's interesting that P0558 is not listed as a fault code in the workshop manuals from MY05 onwards

Buzzard8

Hello Don!

Yes, P0558 is what the car flags up, I've seen it at the garage on the Japanese car diagnostic machine they use. The owner of the garage has taken my car on as something he wants to get fixed, they were the ones who supplied the first Delco Remy alternator (which was tested faulty) and the replacement one which I think we were all just expecting to be fitted and work out of the box. It's driving him nuts now.

As I said in my post from yesterday, the replacement Delco Remy alternator was fitted just over a week ago and it appeared to be working although the voltage never got over 13.2v which concerns me anyway. Does the voltage increase with engine speed? 13.2v was recorded at idle. They didn't want to give me my car back, then next day I'm back down there with the engine management light on and P0558 logged again so they've been moving it round the workshop/forecourt to see if 1). The battery goes flat - it hasn't but it was going flat overnight with the first alternator fitted and 2). To see if the fault is logged. It has behaved itself perfectly until yesterday morning when it was fired-up and the fault logged itself immediately. Clearing it down didn't help - it came straight back when the car was fired-up again.

The guy working on it has got a lot of experience and I'm well out of my depth, hence the reason I've given it to them to sort out as they were happy to do so.

We don't understand why it keeps logging this P0558 fault and why the voltage won't come up above 14v. It's just not behaving as it should. I have been assured that the EMU is behaving as expected and the wiring has been checked and found to be intact with good connections.

I love the car but this is seriously testing my patience and my bank balance.

Smithys STI

iTrader: (1)

Seen this a few times with remanufactured alternators P0558 is a brake booster fault code,not quite sure why this code comes up but Is down to the remanufactured alternator.
use a new genuine alternator or known good second hand one and it will cure your problem.
Its something to do with the smart charge system they use

Buzzard8

Thanks for that. The trouble now though is that I'm into the garage who supplied me the Delco for the cost of that alternator so that could be an interesting conversation if I tell them what you've told me!

I would like to say though that the diagnostic tool they use specifically states "P0558 - Alternator Circuit Low" so if it's a brake booster code, shouldn't it say something else? Also, the brake warning light doesn't illuminate. Do you think that maybe a different brand of recon alternator might cure it, perhaps a Blueprint?

Is it worth doing an EMU reset? I believe that's done by disconnecting the battery for a few minutes and putting the hazards on to ensure the electrical system is completely without charge in it?

As I said previously, I'm out of my depth here so any useful information I will grab with both hands and much thanks!

Smithys STI

iTrader: (1)

I had the same problem with a WR1 that had a re con alternator fitted and showing code p0559 (read using Subaru select monitor) but said it was a brake booster fault code.
replaced the alternator for a genuine one and all was good.
Also had this same situation on a legacy yesterday but P0559 came up with alternator circuit low...again fitted a genuine alternator and it fixed the fault.
The engine light will come back on if you re set the system but it won't come back on straight away as it needs to go through 3 drive cycles first.

Buzzard8

So am I stuffed trying to get my car to work properly with any recon alternator? Why don't they work?

Smithys STI

iTrader: (1)

In my experience re con ones always cause problems....the people who remanufactured them seem to always have problems with the smart charge ones.
just tell them if they can't fix it you want a refund then buy a second hand one from a reputable breaker.

Buzzard8

*** UPDATE #2 ***

Problem solved!

Unable to get the recon Delco Remy alternator to work with my car, the garage (with my permission) decided to source a new Blueprint alternator. Job done, new alternator works a treat!

I'd like to thank each and everyone of you for the help and assistance you've freely given me, it's been invaluable