Check if three pins on the connector are gold... If not, let it change. Solved all my CEL problems...
+1--dielectric grease (or spray-on contact cleaner) is probably the first thing to try.If the pins are gold, then they shouldn't be corroding, and contact resistance will be low (good). If the pins were some other metal, then it is possible to get an oxide layer between then, and then unplugging and re-plugging the connector will wipe the pins and they'll make good contact again...
Even with gold pins, you could be getting something, let's say salt water from the atmosphere down there, and that could cause problems with shorting out the connectors.
I would squeeze some dielectric grease in that connector, that would prevent corrosion and also prevent moisture from shorting out the pins.