2002 Nissan Altima Q&A

2002 Nissan Altima Question: have a p011 code is this the cam sensor and what does it consist of in replacing

car makes a knocking noise -
Answer 1
ck oil level 1st this is very common whn oil is low or dirty -
Answer 2
Along with answer #1 , maybe have 'knocking noise' diagnosed if oil level is okay.May be faulty t-belt tensioner ,or other internal engine problem , making the cam sensor code a secondary issue. -