I think I'd follow the steps for P0335/P0336 before I started disassembling the engine to check the highly unlikely things.
I'm not going to go back and look it up again, but it should tell you to check for the correct voltage on the reference pin, and that the ground is good, and that the signal wire is connected back to the ECM and that you can force it to read RPM counts by momentarily grounding the signal wire. If you can force it to read (fake) RPM, then the sensor is bad.