The switch is located at side of transmission. The diagram shows a slightly darker component, that is the switch. It is also known as Park Neutral Position switch. Are all the indicators on dash for gear position working correctly?
When water gets to electrical connectors, they can cause shorting or open circuits as it can cause oxidations etc. Remove the connector to check for oxidations/rust etc.
Such shorting can cause damages to the PCM as well.
Have you erased the trouble codes and test vehicle before retrieving the codes again?
Tuesday, December 14th, 2010 AT 12:41 PM