Supplu protection unit management supply & addblue pump

[TimWHUFC1969]

HI,

it started when i was getting a random "electrical fault message" in the morning, yet after driving to and back from work it went and never came back. However since the car came back from an MOT i now get this message back, but also the "UREA" light came on, "emissions control", "engine fault" and finally the service light.

I immediately topped up the UREA (add blue), yet the light did not go off and at some point starting flashing.
The car drives absolutely brilliant, no issues other than the dash lit up like a Christmas tree. I was told the battery is over 5 years old so needs changing. I did this and got someone to try and reset the faults. Ironically they all cleared, but after about five minutes driving the "electrical fault", "engine management light" and "UREA" lights came back on and every now and then the "emissions control" in red comes up.
Took it to a garage yesterday and they have carried out a pressure build up test and it came back "failed" i.e. not pressurized so it is not sending the add blue to the injector. Also the "supply protection management unit" (P1624 73) appears to be stuck open.
So after all it wasn't the battery, but looks like it is a pretty easy job to replace the "supply management unit", but will i need to get the fault reset once i change it over?????.

Regarding the add blue tank/pump, as the car is reading the level of add blue in the tank i.e. over the minimum of 1500miles, can i leave it for now and replace the tank/pump at a later date, as it is all very expensive in one hit, and i was told by the garage it just means that add blue is not being injected into the exhaust.
Any advise/help would be very much appreciated.

[GiveMeABreak]

Also the "supply protection management unit" (P1624 73) appears to be stuck open.

That doesn't make sense - the Electrical Supplies Protection & Management unit isn't a valve - it provides protection and management of the power supply. Fault B1624 73 is a Central power switch plus relay status error and generally requires the unit to be replaced.

This may or may not resolve the emissions fault - hard to say on a Forum, but I would fix this issue first.

If the Adblue is not getting from the pump and assuming the pump is still operating ok), then it may be that the Urea injector is crystallised and therefore blocked up. Don't assume you need to have the tank replaced yet.

I would have the injector taken off and examined to see if it is full of white powdery crystals. If so, that will be a cause of the blockage. It can be cleaned up and replaced. I strongly suggest you get some Adblue anti-crystallisation into the tank and use this regularly when filling up the Adblue tank - is prevents crystallisation in the first place and can help breakdown existing deposits in the system:

Wynne's do one: