BMW Turbo Cooling Problem
This bulletin applies to BMW 6-series vehicles equipped with the N63T turbo engine. The warning light may be on after a hot engine restart. When this happens, the engine may have a longer cranking time before starting. The following faults may be stored in the digital motor electronics (DME):
20A504 (turbocharger coolant pump, actuation, line disconnection)
133011 (Valvetronic, supply voltage, malfunction)
133013 (Valvetronic 2, supply voltage, malfunction)
1F0515 (Valvetronic, supply voltage, line disconnection)
1F050F (Valvetronic 2, supply voltage, line disconnection)
The problem is caused by air in the cooling system, which tends to collect in the area of the turbocharger electric coolant pump. When the engine is shut off, the turbo coolant pump impeller continues to spin down in the air pocket. This subsequently generates a voltage that is fed back to the DME, causing the faults to be stored.
Inspect and bleed the cooling system thoroughly and ensure that all connections are tight and sealed. Replace the turbo cooling lines, if necessary.