Hello guys. I have a problem with my 2.5 V6 X-Type. Its been like this for a while. Basically, in winter my alternator was screaming for help in bearings , and charge rate of 12.9-13.1V. The summer came , now its charging 14.9-15.3V. I thought it was overcharging , so I changed alternator regulator, went to my local alternator store to check the alternator, they say its still overcharging 15.3V at idle. Havent put it back in the car, I am wondering what should I do? Can it be that FR or other signal from ECU is faulty? And my battery is bad , 460A left out of 730A. Will be replaced soon, after alternator is fixed.. I have high quality multimeter. It didnt matter if car is just started or was driven for an hour, it still generated 15V. It could be because battery was kinda dead , so ecu tried to charge it at maximum rate all the time? Then local store checked alternator without the control of regulator , so it showed them max it can do?
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https://www.jaguarforums.com/forum/x...nation-202162/

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Well thank you. However , I am not sure what I am supposed to do with alternator charging 15-15.3V after startup, and then going to 15.5-15.6V even after an hour drive in warm weather. Basically, it never drops lower than 15V , even eith new battery and alternator rebuilt. IAT and ECT are working correctly.
Can I manipulate the signal into alternator?

 

If you don't have a top condition battery fitted as you said in your OP, then you're wasting your time and money chasing electrical problems in almost any modern car and certainly in any X type. There may well be nothing wrong with your alternator.

 

Yup, battery is toast, i.m.o. therefore constant high state charging