Blog 8: BMW Valvetronic Motor & Eccentric Shaft Failure
The BMW valvetronic motor on the engine operate as a high-speed actuator that adjusts the intake valve lift, regulating air intake to control engine speed and load. It drives a worm gear that turns an eccentric shaft, allowing for infinite, precise valve lift adjustments to improve fuel efficiency, emissions and power among other parameters.
The valvetronic motor failure issue on BMW engines like the N55, N20, S55 engines is a known problem, especially as mileage increases or maintenance is neglected.
Common Failure Symptoms
Clicking from the engine when unlocking/locking
Engine limp mode
Rough idle or misfires
Loss of power / hesitation
Engine Light (drivetrain fault)
Fault codes like:
2A67 (Valvetronic motor power limitation)
2A6B / 2A6F (position or adaptation errors
P1014 - Valvetronic Reference Eccentric Shaft Sensor Parity Error
P1017 - Valvetronic Eccentric Shaft Sensor Plausibility
P1023 - Valvetronic Adjustment Range
P1030 - Valvetronics Monitoring Sluggish Movement
P10DF - Valvetronic Overload Protection Output Stage System Shutdown
P10E0 - Valvetronic Overload Protection Control Motor System Shutdown
P10E1 - Valvetronic System No Travel Detected
P10E7 - Valvetronic Overload Protection Output Stage Overload
P10E8 - Valvetronic Overload Protection Control Motor Overload
135808 - Valvetronic servomotor position sensor electrical malfunction
135A08 - Valvetronic servomotor 1, position sensors, signal: Not plausible
Why They Fail
1. Wear and Tear
The motor has internal gears that wear out over time
More common after ~70k–100k miles
2. Oil Contamination
Dirty or degraded oil affects the eccentric shaft and motor operation
3. Electrical Issues
Wiring or connector faults
Voltage irregularities
4. Eccentric Shaft Problems
The motor works with the eccentric shaft—if that binds or the teeth are damaged, the motor gets overloaded
Repair Options
In most cases the valvetronic motor can be replaced alone, with the associated hardware and gaskets. The eccentric shaft must be examined whilst the valve cover is removed, if there is damage to the eccentric shaft teeth, this must also be replaced. This considerably increases the cost of repair. Once the repair is complete, the valvetronic system needs to be calibrated using main dealer software.
Our experienced technicians follow BMW’s exact procedures, ensuring your vehicle is repaired perfectly and runs like new.
Whether you drive a 320d or M3, we’ve got the expertise and tools to get the job done right.
Catching problems early can save you thousands in repair bills and keep your BMW performing as it should.
📍 Book your vehicle in today with BM Performance — your trusted BMW MINI specialist.
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