Power battery warning light / service - V50 D4204T 2009

[garyRR]

Hi,

New to the forum.

I've got a new to me November 2009 registered V50.

When I went to start the car the other day, the battery was as flat as a pancake. A big booster pack got it fired up.

When I got home I put the smart charger on recover mode, and all has been well. When I tested the battery, it was able to crank 750A, only 50 short of the 800A rated. The battery is 3.5 years old.

Even with a full battery, the battery warning light and "Urgent Power System Service required" message comes on with high current draw (e.g. lights, heated seats) and low revs (start stop traffic). It usually disappears again with higher revs.

I plugged in diagnostics and found P0625 - alternator field terminal - circuit low.

The vehicle has a brand new RTX alternator on. I have measured the voltage at the alternator with a multimeter, and it is putting out absolutely nothing.

Having read the forum about this warning message on the D4204T, it seems other members have had the same issue even with a brand new alternator, and the car needs a genuine alternator to clear the message.

Before I go ahead, does this seem correct diagnosis and route of action?

Secondly, as I don't have the original alternator, I'm struggling to find the correct part number. On this model and registration, is it a Denso or Bosch, and what is the part number? Looking on Partsuoq, it suggests multiple numbers. Main Dealer weren't willing to divulge.

Is a Denso DAN930 fine?

[iainmd]

What rating was your old alternator? Many were fitted with 120A alternators and the replacements are 150A. The car needs a software update from Volvo if it didn't already have a 150A alternator.

As an aside, I'm currently suffering the joys of alternator problems (the voltage regulator on it rather than the alternator itself). We had a non-Volvo one fitted in an emergency when the alternator failed away from home on holiday and the car broke down. It's been OK for 2yrs but now the car is throwing "EL CURRENT HIGH STOP SAFELY". Spoke to the garage and apparently Ford/PSV/Volvo engines can be really sensitive to aftermarket alternators. Mine's going in on Monday to get a genuine Volvo alternator fitted and I hope that solves the problem.

I'm really looking forward to getting the gold plated alternator installed. I assume it must be at £389! Even if it does fix it that is daylight robbery for an alternator.