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The past month or so I have been replacing the N52 in my sisters 2011 X3 28i as the old engine suffered sheared vanos bolts. During this I went ahead and replaced all the common maintenance items such as the water pump, thermostat, engine mounts, and all of the common gaskets that fail. All parts were ordered from FCP. Last night I installed the radiators and filled the system so I could test everything. The car started great and ran great, however the CEL was on. I checked the codes with ProTool and got 20AA04 "electric coolant pump: missing" and two other codes for the ambient air temp sensor and oil pressure control valve being unplugged. The water pump is of course plugged in. I checked the water pump speed and it shows as 0. I am fairly confident the BSD bus is operating as the oil level sensor is working fine and the alternator is charging at 14.6V. The only things missing/unplugged are the head lights, fog lights, front impact sensors, ambient air temp sensor and the oil pressure control valve. Would these parts being unplugged cause this issue with the water pump or is the new Pierburg water pump just DOA? I already ordered a replacement water pump from FCP but I just want to make sure that really is my problem. A new oil pressure control valve is ordered also as the original was stuck in the old engine and broke instead of coming out smh.

Nuclear engineer
02/2012 X5 35d M57Y CPO 121K miles NOKIAN WR G3 30K miles
23,954 Posts
BSD components are on individual lines to the ECU, not a common bus.

ECP are fragile, particularly their Graphitar journal bearings, very soft and easily corroded.

They must always be wet with proper coolant anti-corrosion. They must not be dropped roughly handled. They should be stored with the impeller horizontal and the journal bearings not static loaded - the thrust bumper will be loaded. The Brush-less DC motor cannot provide breakaway torque, the impeller must be turned by hand at the last accessible instant. ISTA has a first start routine that may apply breakaway torque.

BMW TIS suggests vacuum filling. An ECP run dry is instantly ruined.

The technology is quite the same as my 1,000 Hp coolant pumps.

BMW F25 X3 xDrive28i SAV / Repair Manuals and Technical Data / 11 Engine / 11 51 Coolant pump with drive /
11 51 000 Removing and installing/renewing coolant pump (N52)
[ … ]
Risk of damage:
Non-visible damage to the coolant pump.
Forcibly removing, installing or dropping the coolant pump down will damage it.
Remove and install the coolant pump without damaging it and without applying external force.
Avoid impacts/knocks to the coolant pump (e.g.. by tools, falling down, hard contact with base).
Necessarily renew the coolant pump after it falls or receives hard blows.

[ … ]

Installation note:
If the coolant pump is to be reused, it must be mechanically rotated once (breakaway torque at impellers).

One coolant pump rotation will be sufficient.

Assemble engine. Bleeding instructions must be observed without fail.

BMW F25 X3 xDrive28i SAV / Repair Manuals and Technical Data / 11 Engine / 11 51 Coolant pump with drive /
17 00 039 Bleed and fill cooling system with vacuum filling unit
Rectangle Slope Schematic Font Parallel
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