Something as simple as checking the DTCs can go off the rails when the code isn’t translated properly by your scan tool.
This case study involving three failed PCMs in a 2002 Honda Civic illustrates the real-world complexities of diagnosing on-board modules linked together by a bus communications network.
Sometimes simple = complex. For example, the modern coil-on-plug (COP) ignition system is perhaps among the simplest to diagnose, but to illustrate the complexities, let’s look at how a 2008 Toyota Tundra 4.0L V6 might record various misfire codes.
Due to fuel intrusion into the low-pressure system fuel pressure sensor (G410), a false signal may be sent to the controller, resulting in a reading that is out of tolerance. Model: 2007 Audi A4 Sedan V6-3.2L Scenario: The MIL is on and one or more of the following DTCs is stored in the engine control