I have a 2005 sti type UK.. i replaced alternator with a brand new, oem Subaru AA420. This did remove obd p2503 code for up to the last 15months. Today like any other day over the last 3 months. Say every 2 or 3 days this P2503 code appears when i test the voltage at idle the output voltage under load is 14.1 volts even with the andlight on. I belive there is 3 items covered by this p2503. 1)charging system voltage low. 2) fuel system which iv never had an issue since owned as car is serviced 3 times a year. 3) seemingly an associated electrical component but which one???...please help.
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