p0302 2006 nissan maxima

Question

Car is overh and rpm indicator on the dashboard is fluctuating. i took it for scaning and got p0302 and p0603. How do i know exactly what needs to be fixed?

Answer 1

Neither of both codes related components will cause the engine to overheat, that must be something else. 

The p0302 means that one of the cylinders is misfiring and could cause the RPM to fluctuate.

The P0603 is related to the Engine Control Module, but won’t cause any of the symptoms to mention.

You should start by checking for coolant leaks which could cause the engine to overheat. At this point that’s probably the most important problem.