BMW Valvetronic eccentric shaft failure

BMW Valvetronic eccentric shaft failure can happen suddenly. You go out to your vehicle unlock the doors, and before you even start the vehicle, you notice a terrible clicking/ binding noise coming from the engine bay. You start the car and there feels to be a slightly rough idle, but other than that, all is ok. Shortly after, you get a light on you dash. A service engine soon or check engine (CEL) appears on the dash. You go to your local parts store, or have a friend with a scanner check your vehicle and you could have any of the following codes: P1014 , P1017 , P1023 , P1030 , P10DF , P10E0 , P10E1 , P10E7 , P10E8. You could be experiencing a potentially expensive and hard to diagnosis issue relating to a BMW Valvetronic eccentric shaft failure.

The Valvetronic system on your bmw is a variable valve lift setup which, in combination with variable valve timing, allows the intake valve timing to be infinitely adjustable. The electric valvetronic motor was first on normally-aspirated engines but is now common on the turbocharged vehicles as well. It is responsible for actuating an eccentric shaft that adjusts intake valve lift. The motor itself is pretty reliable and does not fail too often. It’s basically a camshaft on top of the intake camshaft that controls how far open the valves move during one rotation of the intake camshaft. This means a BMW with valvetronic effectively negates the need for a throttle body, increases efficiency by minimising pumping losses and improves fuel economy and emissions.

This customer’s 135i with the N55 had it’s check engine light come on. Faults were for the valvetronic motor and valvetronic not reaching its limit. We performed the test plan which runs the valvetronic through its operating range and relearns the position. However, when the engine was started it would fail again and fault with one of the following BMW fault codes: 2DBA , 2DBB , 2DBC , 2DCA , 2DCB , 2DCE , 2DCF , 2D42 , 2D43 , 2D44
After a little more testing we finally made the conclusion that the valvetronic eccentric shaft had gone bad. The shaft over time and mileage wears in certain spots that cause the movement of the shaft to bind. This increased resistance is picked up by the computer monitoring the motor and a fault is thrown.

The Valvetronic eccentric shaft needed to be replaced. Removing it requires the removal of the valve cover. Special BMW tooling is required to release tension from the shaft springs and levers. Even with the tool, it is very easy for a spring to jump off and be in a position that can potentially cause catastrophic engine failure. After the repairs are performed on the Valvetronic assembly, the limit stops have to be relearned using the BMW scan tool to do this procedure. The limit stops are the mechanical limit stop, end to end of rotation of the eccentric shaft. The DME (digital motor electronics) records these stops via the eccentric shaft sensor to determine mechanical adjustment limits of the eccentric shaft. This is why the faults occur, the end stops are not correctly sensed when doing the precheck, or in this case, extra resistance from the shaft made the time to reach the limits longer than spec. Whit the new shafts in place, the vehicle was back to smooth fault-free running.

Do you suspect your BMW Valvetronic eccentric shaft failure issues? Don’t hesitate to get your car checked by the experts at Fluid MotorUnion. We have the equipment, experience and the desire to fix your vehicle right the first time. Email with any questions, or drop us a call at our Naperville location by calling 630 305 3054.

BMW Valvetronic eccentric shaft failure