Question 1

What do P03xx ignition and misfire codes mean?

Accepted Answer

P03xx codes cover ignition, cylinder-misfire, crankshaft-position, and camshaft-position faults. The code narrows the monitored circuit or combustion event; it does not automatically identify the failed part.

Question 2

Should I replace the ignition coil when a misfire code appears?

Accepted Answer

Not necessarily. Check the freeze-frame, misfire counters, spark plug, coil, injector, wiring, air leaks, compression, and timing signals that fit the code before approving a replacement part.

Question 3

What is the difference between a cylinder misfire and an ignition-coil code?

Accepted Answer

A cylinder misfire code reports a combustion event that did not contribute normally, while an ignition-coil circuit code reports an electrical or driver-circuit condition. A coil problem can cause either type, but the two code families need different confirmation tests.