The dreaded “Engine Malfunction – Reduced Power” message appears on your dash as soon as you take off in your E90 M3. There is a good possibility this is due to the notorious throttle actuators and the associated plastic drive gears. Each 4.0L engine is equipped with two throttle actuators that control each cylinder bank (Note -the bank 1 throttle actuator is actually located on the bank 2 side, vise versa). Inside each throttle actuator is a set of plastic gears, the gears will begin to wear the teeth very thinly over time, typically in the idle position. It creates play between the gears and the DME engine computer flags the issue.
Most common fault codes set:
2B15 – Throttle Valve Actuator Governor Monitoring/Control Bank 1
2B16 – Throttle Valve Actuator Governor Monitoring/Control Bank 2
2B21 – Throttle Valve Actuator Pre-drive Check Bank 1
2B22 – Throttle Valve Actuator Pre-driver Check Bank 2
2B25 – Throttle Valve Monitoring Bank 1
2B26 – Throttle Valve Monitoring Bank 2
27A1 – Throttle Valve Actuator Enable Line Bank 1
27A2 – Throttle Valve Actuator Enable Line Bank 2
2B57 – Safety Concept Manager Action
CDCD – Throttle Valve Actuator CAN Message
There are two avenues to choose from when faced with this repair:
- Replace the throttle actuator(s) with the latest updated unit from BMW, these are very expensive.
- Rebuild the old units with updated gears.
Either repair will require the entire intake manifold to be removed. After the repair is made, a throttle actuator adaptation is required. There is no need for any coding with new units.
If this issue has been popping up for you, be in touch, we would love to work with you to find a solution.