Smart Alternator

[Wackapayne]

Having a weird problem

Car started check engine light p2503 low alternator voltage. Did loads of test pointed to alternator that's before I knew it was ECU controlled one.

New alternator same issue

All earths, ect are good. My ECU is not detecting load.

How can I fool this ?

Does anyone have a 2006/07 WRX wiring diagram all mine are for US version and don't have a 4 block ECU.

Does cutting the blue wire just allow the alternator to run constantly.

 

 

[stuartie]

If it's the same kind of idea as the fiat panda then you will have to tell the ecu that it has the new alternator using a diagnostic machine, we found that out at work when we fitted alternators to the 4x4 pandas, took us ages and a phone call to fiat to find that out 👍

[Mr B]

What new alternator fitted ?, reman of many brands can not be up to spec and system sense control will have issues .

You either want an oem original alternator or blueprint, we tend stick to original oem as much as possible as issues with reman and aftermaket is highly common and we don't have time keep swapping duds or want reputation issue due to current parts trend for junky poor spec and quality .

you can do some tests at ecu to see sense control working and blue wire alternator grounding switches correctly (grounds this wire to reduce alternator output) .

[Wackapayne]

Ok,  I have resolved the issue  somewhat. The alternator was an aftermarket forgot the brand. It works fine as does the original OEM. The issue is the ECU command signal shows 2.5v no matter the load. I did a continuity test and was find. I also loaded tested every wire very low 10 - 50 mvs.  I removed the blue command wire from plug and the alternator started working as expected around 13.8v - 14.4v.

 

Does anyone know what voltage the blue wire should give out? I have decided to make a mod and remove the DTC in the map for this file and monitor the Battery voltage myself.