P0304 Toyota -

Question

If the clip on the wire harness that clamps to the #4 coil broke off, would that cause p0304 error code

Answer 1

HI there,

It is possible this would cause the problem if the wires aren't pushed all the way on then the coil may not fire. I would take a small screwdriver and push the wires from the back to make sure they are tight on the coil.