First a little background. Problem started with a P0340 Camshaft Position Sensor. Replaced the sensor and cleared the code and it started. Next day I went to drive the truck, and it wouldn't start again. The P0340 code was back, cleared the code and it ran. Shut it down and it wouldn't start again. Cleared the code again and the truck started and I was able to drive it and it restarted with no problems. Fast forward to today, went to start and no start. Looked at the codes, P0340 is back and now the codes will not clear. Could I have damaged the ECM? I'm at my wits end Any and all help is appreciated. I looked at other posts about the P0340 code and none seem to fix my problem.