Short version of my question for 2003 E320 Wagon 4Matic (W210). Which crankshaft position sensor should I get, Bosch or Hella? They cost about the same.

Here is the long version. Your reading and comments are deeply appreciated.

A couple of days ago when I start the car in the morning, the check engine light did not turn off. After a couple of re-starts (checking the fuel filler cap, etc) and drove it for about 45 minutes and the CEL turned off by itself after a stop in a store and a re-start. The CEL has not turned on.

Went to Autozone to pull any stored code (CEL was NOT on) and there was a stored code P0355 that indicates malfunction of the crankshaft position sensor circuit. The strange thing is that that code cannot be erased by their scanner so the guy said it might not been trigged by the light the day before.

The car did not have any start/stalling or idling problems. Everything is normal.

After a lot of reading on various forums about this sensor, I was finally able to locate it. I unplug the connector and saw a bit corrosion so I cleaned it and the sensor contacts with electric contact cleaner. I was also able to feel with fingers that E8 bolt and put on an E8 socket (1/4 drive) but did not unbolt it. It seems that the unbolt and re-bolt of that bolt is completely by feel because I cannot see the bolt head. I was afraid not being able to put it back once I take it out because I have not experienced any trouble yet.

I also decided to clean the MAF and got the "right" security torx bits but I was totally stumped. The screw heads on the MAF insert have only 5 spaces but the torx bits have 6. I read many people who were able to remove the screws with T25 security torx bits but mine could not go in enough to remove the screws. Did MB or Bosch changed these screws so no one can easily remove them?

Thanks,

I have seen the five point torx security fasteners on VWs. I grabbed the circumference of the fasteners with channel locks (water pump pliers). After I backed them off a bit I could turn the fasteners with a straight blade screwdriver slipped between the security pin and a couple of the points.

Thanks, Vince.

I tried various pliers but the screw heads were so tapered and everything was slipping off. I finally just sprayed a lot of contact cleaner to the sensor without removing it.

I also ordered the Hella CPS.

An update:

I received my Actron CP9175 scaner today and plugged it in.

That P0335 code Autozone cannot erase disappeared. That must be a pending code and my cleaning might have made it disappear. It is good now that I have a scanner so I can see freeze-frame data if it comes on again.

I do have the new Hella sensor in the car, along with the necessary tools to replace the CPS.