Odd bod of a fault, as follows:-
So, I have a 2010, 2.0Hdi X7 Estate, which has the BECB module (BOSCH 9664448980) attached to the battery negative terminal.
Every so often (mostly in the morning after 5 minutes of driving (every 3 or 4 days or so) I get the battery charge warning along with the dong, dong, dong gong, it then disappears and isn't seen for another 3-4 days.
I have a DMM attached at point of failure which tells me alternator is kicking out around 14.2V
This started last year (would happen once every so often e.g. every 3 - 6 weeks, but now frequency has increased) and since then, alternator, battery, and BECB have been changed, intermittent fault remains.
The BECB was changed by a garage as I gave up trying to fault find (at that time I had no decent diagnostic device). They said the BECB was reporting incorrectly to the BSI, so £200 later fault still the same.
So happens, I now have access to a Foxwell NT644, it tells me the battery voltage is 12.2V (reported BECB ECU) but when measured at the battery is 14.2V, so I have a 2V error.
But the BSI reports voltage as 14.2V and a secure battery voltage of 12.2V,
Now, where does this 12.2V "secure battery voltage" come from ??????
So any ideas ??????????????, think I'm homing in the right direction though !
Any help much appreciated.