One problem related to check engine light on has been reported for the 2006 BMW 750. The most recently reported issues are listed below.
The contact owns a 2006 BMW 750li. The contact stated that the check engine warning light illuminated. The vehicle was taken to the dealer for diagnostic testing which located the failure as the engine thermostat. The dealer replaced the thermostat twice under warranty but the failure was not corrected. The check engine light remained illuminated and the vehicle would lose power. The vehicle was taken back to the dealer who performed another diagnostic test which located the failure as the engine wiring harness. The vehicle was not further repaired. The failure mileage was 52,000 and current mileage 83,000.