Originally posted by Silversvts:
My car was showing a P0302 code which is a cylinder 2 misfire. I had it checked by the scanner at Advance Auto and also by Tony2005's scanner. So I take the car into the dealership and they're saying that my #6 fuel injector is bad. Why is the dealership saying the #6 injector is bad and two other scanners saying #2 cylinder? Is the dealership wrong or is their computer just more accurate and the scanners are wrong?

Thanks



The OBD-II system does allow dealer-specific codes, these codes will be a P1xyz code and may include codes for fuel injectors, etc. I have an OTC Genisys scan tool which will allow me to retrieve the dealer-specific codes as well as monitor some dealer-only parameters in the datastream mode. There are parameters for fuel injector faults which the Autozone readers will not see but show up during the datastream mode.

The misfire indication uses the knock sensor and camshaft position sensors to determine which cylinder the PCM thinks is misfiring. There is a [small] chance that a bad injector on cylinder #6 could cause a misfire on cylinder #2 report.

What I would do is use my scanner to determine if the air/fuel ratio is going lean or rich during a "misfire" to determine if unburned fuel is getting into the exhaust. If the mixture goes rich, then you probably don't have spark (which would indicate a bad plug, wire, or coil). If the mixture goes lean, then you may not be getting enough fuel (bad injector).

Do cylinders 2 and 6 share a coil by chance (I don't have my service manual handy)?

-Rod