20 June 2022
BMW engine management light on, rough running or will not rev up
Affected Vehicles BMW E9X series (2006 - 2012) | M3 | MSS60 Symptoms Engine management light on Rough running Will not rev up Various fault codes stored in the DME in relation to throttle body Faults 2B1F Throttle valve sensor, bank 1 Engine - DME 2B20 Throttle valve sensor, bank 2 Engine - DME 2B21 Throttle valve actuator pre-drive check, bank 1 Engine - DME 2B22 Throttle valve actuator pre-drive check, bank 2 Engine - DME 2B23 Idle actuator governor monitoring, bank 1 Engine - DME 2B25 Throttle valve monitoring, bank 1 Engine - DME 2B26 Throttle valve monitoring, bank 2 Engine - DME 2B27 Throttle valves, test of return springs, bank 1 Engine - DME 2B27 Throttle valves, test of return springs, bank 2 Engine - DME Possible Causes 1. Worn Plastic Gears Gears Worn Gears Worn 2. Dry, loose or burnt soldered joints Circuit Defective Repair Steps 1. Carry out a functional check Confirm the customer's complaint. 2. Carry out a quick test Quick Test 3. Check the fault codes stored in the DME DME Code 4. If the fault is stored for one bank only i.e. Throttle body pre-drive check Bank 2 (2B22) start by swapping the throttle bodies over from Bank 2 to Bank 1 and vice-versa. If the fault travels to Bank 1 then the cause will be the throttle motor itself. If swapping the Throttles over the fault code did not travel and change sides then the wiring would need to be checked and or repaired between the DME and the Throttle that is stored as faulty. If the wiring checks proved to be OK, then it would indicate a faulty DME but that is a very rare repair. 5. Strip the throttle down and check for wear in the plastic gears and also check for loose, dry or burnt soldered joints on the transistorsstrip the trstrip the throttle down and check for wear in the plastic gears and also check for loose, dry or burnt areas. See Images In The Causes Section. The soldered joints can be cleaned and re-soldered. The plastic gears can be replaced but the replacement parts are not from BMW. Only a replacement throttle motor is available from BMW. 6. After the repair you must run the Throttle valve actuator test. The DME will run the motors from min to max positions and will learn the end stops. To do this go in to DME >> Service functions >>Throttle valve group test >> System test Throttle valve actuator. Group Test Actuator Commands 7. The car is fixed when the engine runs correctly and there are no Throttle related faults stored. Tools Required Small electrical tools for stripping the throttle body Soldering iron and solder Parts Required Throttle body