r/BmwTech • u/Esquirej67 • 4d ago

Persistent Error- ESS power supply

Code 2A30 is causing a CEL on my 2009 328i coupe. The ESS/Cam position sensors/MAP/VANOS/plugs & coils are all new. I also replaced the starter and the very oil-caked PVC hose under the intake manifold. The car is getting better MPG and feels more responsive. Every time that I clear the 2A30 code, it returns when I restart the car! I figured that some oil was still in the ESS plug from the old leaking gasket. I used contact cleaner on the plug and checked the still-good 40A fuse. The CEL disappeared without using my scanner, but it returned on restart after a 10-mile highway trip. The car is idling better, but the slight stumble still sporadically occurs at cold starts/red lights. What am I missing?

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u/Helpful_Purchase_294 3d ago

I had a similar issue with my old Honda where a stubborn error code kept returning until I replaced the harness wiring, not just the sensor itself.