This bulletin applies to 2014 BMW 6 and 7 series vehicles equipped with the N63T engine. The check engine 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 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 ISTA test plans may be inconclusive as the circuits check as good and this problem may be difficult to reproduce. 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 turbocharger 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 make sure that connections are tight (turbocharger cooling lines and crimped hose/line fittings). Replace the turbocharger cooling lines if necessary. Bleed the cooling system as described in repair instruction 17 00 039.
