This code comes up about every 300 miles. I check with my OBD II, then erase it because the truck seems to be running fine. Will this get worse and cause some engine function to fail?
P1391 Intermittent loss of CMP or CKP
This is intermittent loss of Cam position sensor or Crank position sensor. Sensor do fail it does get worn out, If the CKP sensor fails and your driving the engine will just stop running and there will be restart until this is corrected, If this the CMP the vehicle hesitiate and run rough and may even stall out. You can either hook up a labscope to determine which one is failing or just replace both sensor.It is to your advantage you replace both sensor.This diagram is for a 3.9 engine size, different size engine uses different sensor and location.
36.2k questions
32.2k answers
1.3k comments
22.8k users