This 2009 BMW Mini 1.6 came in with very poor running, hunting at idle and a fault code for the Vanos inlet actuator movement. The Vanos system controls variable valve timing and the solenoids that operate it are fed by engine oil — meaning any metal debris in the oil will accumulate on the solenoid gauze and restrict it.
On inspection the inlet Vanos solenoid had already been cleaned and its code cleared. The exhaust solenoid however was completely blocked with metal filings. The gauze was full of debris and the valve movement was restricted. This guide covers diagnosis, cleaning and refitting — and what to do if it comes back.
Symptoms of a Blocked Vanos Solenoid
- Engine management light with Vanos-related fault code
- Poor idle — hunting, almost stalling
- Very rough running especially when cold
- Reluctance to rev up smoothly
- Code returns after clearing (if solenoid not cleaned)
Tools & Parts Needed
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Step-by-Step Guide
Scan for Fault Codes
Connect a diagnostic scanner and read the fault codes. On this Mini the code was for the Vanos inlet actuator movement. Note all codes — there may be multiple Vanos codes present. Once noted, do not clear them yet — confirm the fault first.
Remove the Front Airbox Section
The front section of the airbox is held by T25 Torx screws and one 10mm bolt. Remove these and lift the front section of the airbox clear. For the main airbox body: undo the 10mm bolt, then lift the airbox up and out of its locating point.
Remove the Throttle Body Elbow & Breather Pipe
Undo the Jubilee clip on the elbow pipe that connects to the throttle body and pull it off. Remove the small breather pipe from the same area. This improves access to the Vanos solenoid on the side of the engine.
Unplug & Remove the Vanos Solenoid
You will see both Vanos solenoids — an exhaust one and an inlet one on the cylinder head. Unplug the electrical connector from the solenoid you are removing. Undo the single 10mm bolt on top of it. Wiggle and pull the solenoid out. On this one the gauze filter was completely coated in metal filings.
Clean the Solenoid
Spray brake cleaner thoroughly onto the gauze end of the solenoid, working it into the mesh. Work the valve pin with a small screwdriver to help free any debris. Continue cleaning until the gauze is clear and the valve moves freely. Allow to dry fully before refitting.
Refit, Clear Codes & Test
Push the clean solenoid back into position and refit the 10mm bolt. Reconnect the electrical plug. Refit the throttle body elbow, breather pipe and airbox in reverse order. Start the engine and clear the fault codes with the scanner. Rev the engine and let it warm up — on this Mini the hunting idle immediately improved and the code did not return.
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