Q: Replaced the camshaft position sensor and still goes into safe mode ? 2000 BMW 740i

Hi there - I believe your real problem is a failed timing chain guide, which has shifted the cam timing beyond what the sensor can deal with. This is a common problem with BMW V8s with extended mileage. The solution for this is a thorough timing chain service - which includes the chain, tensioner, chain guides, and seals. I recommend a timing chain service performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs. Note: if the water pump has not been service in recent history, you may consider replacing the water pump while the engine has been disassembled to this point - save repeated labor cost.