Rpm sensor failing the self test at startup and throwing the Service message. All good after starting the engine. No other issues.
Had the same issue a couple of years ago coupled with a few other problems, progressing tappets failure being the most prominent. Last time the issue was water ingress and corrosion due to a pinched silicone seal in one of the connectors for the ECU.
I was sure that was sorted last time and startet with the sensor and worked my way back, only to arrive at the ECU connector once more. Water and corrosion again, seal was splitted under the lever hinge for the connector.
After cleaning and trying to get the connector sealed again I discovered that the neutral lamp did not work anymore. After some more checking I discovered that the pin (#23) in the ECU was missing after my cleaning. I later found it the broken off bit and it was corroded so thin that it would have to break in any case.
I made an improvised pin work, and I hope a drop of silver epoxy will keep it connected. Seal was fixed with silicone to the connector, and I used some grease on the outside to keep the water out. Function testing passed, so now it is time for durability testing...[You must be registered and logged in to see this image.]