I work for Autozone and the company provides us with a handy little booklet to help us diagnose OBDII codes. Heres what it says for a P0340 code. The most likely cause for that code is the cam position sensor is defective. The 2nd is the connector and/or the wiring to the sensor, you've already checked for that and it was good though. The least likely cause is an engine mechanical problem-the timing chain. My advice is to pull the sensor off the engine, run it downto your local Autozone, if you have one, and get it tested. I think you're gonna be spending the $300+ bucks for a new sensor though.

Chris