Fault code P1245-35-10?

Check engine light came on today." Fault code P1245-35-10, intermittent, start of injection timing regulation controll deviation". My Bentley manual said "P1245 Needle lift sensor circ. short to ground". Px2xx means measurement of air and fuel. P1xxx means Manufacturer codes for additional emmision system function. Checked my injection timing and it was advanced but within spec.- just like I set it after timing belt change 20k miles ago. Car is running fine but light is worrisome. I guess my question is where would you recommend I start? ECU? Is the needle lift sensor in the injection pump maybe? I'm not very forum-savy but I did search this code and didn't find that exact p-code on this forum.

The needle lift sensor is inthe #3 injector. Pull apart the connector and be sure the pins are all in good shape: no bent pins, corrosion, spread sockets, etc. I have read that that is the most common problem there.

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