M5 went into limp mode and is running lean

repgarage · 03-18-2025, 11:06 PM

I started my car and it went immediately into limp mode, I read the codes with a scanner 2B3A, 2B57, 2796, 2B47. Car runs good for up to 30 seconds then runs rough anyone can chime in?

aade · 07-17-2025, 02:51 AM

Throttle actuators on both banks. Measure battery voltage (you should really see other issues as well) to rule out alternator or battery.

The actuator codes are likely the root cause and the other codes where the DME complains that it can’t read throttle actuation are likely cascading faults.

Try to clean the actuators and failing that inspect them for wear. If they’re stuck it could be mechanical wear and they’d need a rebuild or replacement. If dirty you might get away with a good thorough cleaning.

03-18-2025, 11:06 PM	#1
repgarage Registered 0 Rep 2 Posts Drives: Join Date: Nov 2024 Location: Florida iTrader: (0)	M5 went into limp mode and is running lean I started my car and it went immediately into limp mode, I read the codes with a scanner 2B3A, 2B57, 2796, 2B47. Car runs good for up to 30 seconds then runs rough anyone can chime in?
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07-17-2025, 02:51 AM	#2
aade New Member 5 Rep 82 Posts Drives: BMW E61 5er Join Date: Jul 2025 Location: Stockholm iTrader: (0)	Throttle actuators on both banks. Measure battery voltage (you should really see other issues as well) to rule out alternator or battery. The actuator codes are likely the root cause and the other codes where the DME complains that it can’t read throttle actuation are likely cascading faults. Try to clean the actuators and failing that inspect them for wear. If they’re stuck it could be mechanical wear and they’d need a rebuild or replacement. If dirty you might get away with a good thorough cleaning.
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