I know this has to do with the emission control circuit. It is not the fuel cap (replaced). This is what happens generally. Clear all codes, after about 100 miles low fuel light will blink even though tank is 3/4 full. Turn off engine low fuel light no longer blinking. Usually within the next 5 miles the cel and check electronics lights all come on. You can drive it like this for maybe 10 miles then when you try to start engine cranks but no start. Clear codes and the thing starts all over again. Mechanic replaced the crankshaft position sensor and the camshaft position sensor. It started immediately after both of these replacements but it always comes back to the same problem. Sorry this is so long but it has been going on for 3 months anyone have any ideas?

 

My best guess would be a failing Overload Protection Relay-(K40 Relay).
This is a common failure module, that can cause a wide variety of issues.

MB# 2105400072
Sub Category: Engine Electrical
Description: Overload Protection Relay-(K40 Relay)
Application List:
W170.435, 445, 447
W210.055, 072, 272
W463.206, 209, 232, 233, 240, 241
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

whunter@pelicanparts.com


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I borrowed a K40 relay from my brother. Car started right up no CEL no problem drove 300 miles today started every time and ran better than new. I think I will keep this relay and give my brother my old one see if he has problems with it HEHE.