Land Rover Repair: 2000 BMW 740iL 123K manf. 5/99, 2000 bmw 740il, bmw 740il

Question
Good Day John!

Your credentials are impressive and I hope you may be able to help me with some issues I'm having with my car.  The main problem is that she shuts off randomly.  Not a stall, but a shut off, just as if I were to turn the ignition off.  "Engine Fail Safe" sometimes displays on the cluster but not always.  Also just before it stalls, the rpms drop and the car bucks a little.  Once I put it in Neutral or Park she'll start right up and be fine.  It seems to happen when I'm idiling, coming to a stop, or preparing to make a turn.  This same problem existed before these recent repairs less than 500 miles ago: New throttle body, fuel filter, new coil on cylinder 4, & vacuum leak on intake hose repaired.  I also cleaned the MAF with electronic spray and cleaned my K&N air filter.

Its been giving the following codes as well: P1531, P1174, P0500 & P0605

Any help would be greatly appreciated.

Thank You,

Mike

Answer
The most common cause of that in the 740 engine is crank or cam sensor failure.  There is really no test for it; you change the sensors and see if it's fixed.  The problem is, when the crank sensor fails the computer thinks the engine simply stopped turning and shuts its program down.  It never sets a fault code.  So there is no diagnostic evidence.