Needing help with my Impreza R Sport and I appreciate those who do so.

The current issue is my EML is coming up with error code P2503 - Charging Circuit Voltage Low

I measured the voltage over the alternator, and it was 12V, so I ordered a used one online. Fitted that, didn't work, error code still present. Decided to buy a brand new Lucas part online. Fitted that, cleared engine code, but still have the engine management light on! It would appear the alternator is not engaging.

So, I started trying things I could find on the internet. I removed the blue cable from the connector (CSL), nothing, I tried with the parking lights on with no success and have now have no idea on how to progress. The car starts easily, and the grounding seems OK. The battery is pretty new (max 1 year) and should be good for the job.

I appreciate any advice on this. I understand this is a difficult thing to help with as presumably there are a lot of possible causes. I noticed on FREESSM the alternator duty did not chnage when lights or AC were turned on.

thanks

 

If there's no Control wire connection the ECU can't control the output as they are so called "smart alternators".

Most people end up purchasing the OEM alternator 23700AA521 /23700AA522
Same for MY07 Hawk or 2007 registered MY08 Hatch
Worth reading these threads
https://www.scoobynet.com/engine-man...low-fault.html

 

PSA - Turns out the charge light bulb fell out of the binnacle causing this issue.

Drove over some particularly aggressive cobbles a couple of days before this issue presented itself. Worth checking if this issue is affecting you too!

Please ensure the charge light turns on when starting car.

 

YES - this!
With the ignition on, but before you start the car, check the red battery light is illuminated.
If no battery light and a 3-wire plug on the alternator:
Check the battery light bulb in the dash being blown or fallen out, weirdly, the charging circuit is wired through the bulb!
Or, if the start circuit in the alternator is faulty, you also get no battery/charging warning light, so no indication that the alternator is not charging.

With the ignition on, if you disconnect the 3-wire plug and ground the female metal connector (which is in the plug) attached to the black/white wire, you should read 12V.
Again, with the ignition still on, if you re-connect the plug to the alternator and then ground from the back of the metal connector on the black/white wire, you should read 0.5-0.8V. If you are still reading 12V the alternator is faulty.

After replacing the alternator, I still had to clear a new orange engine fault warning light, via the OBD2 port, as this was stored as an old charging fault.

Had I noticed no battery light on start-up, I may have avoided getting removed from the M69!

Trying this:
Rolling Component (Rollco) ALT211 £100 -£120.
https://www.rollingcomponents.com/product-detail.php