Self-Diagnostic System

NOTE: Fuel system self-diagnostics and ignition system diagnostics are covered separately in this article.

The fuel injection system and ignition system feature a built-in self-diagnostic function for fault tracing. A common diagnostic unit, located in the engine compartment behind the left strut assembly, interfaces directly with either ECU. The diagnostic unit has a push button, a Red Light-Emitting Diode (LED) and a selector (coding) cable. See Figure .

Once the selector cable has been inserted in the correct slot, depressing the button once, twice or three times selects from one of three control (fault tracing) functions. Faults stored in ECU memory are read via a system of LED flashes. All fault codes have 3 digits, each capable of ranging from 1-to-4 digits. Since codes all have three numbers, each code requires three series of flashes. For easier reading, a 2.5-second interval separates each digit of the code.

Socket No. 2 in the diagnostic unit is used for fuel system testing. Socket 6 is used for ignition system testing.