2005 Lincoln Aviator 4.6L displays the P0340 DTC — Camshaft Position Sensor “A” Circuit Bank 1 or Single Sensor.

The truck seems to run fine but I hear a little chatter at start from the timing cover. My diagnostic plan is to inspect and prove out the CMP circuit then analyze the systems control signals with a Scope

I did a visual inspection of the wires and connectors and saw nothing of significance. The CMP cam position sensor is a 2 wire configuration with Module control and signal return.

I did a Pinpoint testing procedure and found no opens or shorts, Cam sensor is new at tested fine. I disconnected the circuit at both ends, ran a jumper on one side with a 3a bulb which lit bright. To validate the connectors I checked voltage and continuity/resistance on both component and harness sides separately then together.

At this point I decided to scope the CMP and CKP ( cam and crank sensor) signals to see what the PCM Engine control module is getting. The CMP cam signal is blue and the CKP crank signal is green.

With the data in hand I compared it to known good 4.6 wave forms for analysis and there were obvious variations.

The crank signal had big amplitude oscillation which was different from the good wave forms consistent level.

Additionally it appears that the timing between the Lincoln’s Cam and Crank are off with the Cam being slightly retarded.

This is likely the cause for the persistent P0340 DTC. The vehicle appears to need a timing chain as it has started to stretch.

I would need to pull the valve cover and inspect the VVT solenoid and chain for signs of wear.

I will check with the owner to see what they want to do next.