Theory Of Operation

This diagnostic checks for the availability of the Engine Status signal which is sent by the Powertrain Control Module (PCM) via a CAN message. The Engine Status possible values include the following: 0) engine stopped, 1) engine starting, 2) engine idling and unstable, 3) engine idling and stable, 4) engine running and unlimited RPM, 5) engine running and limited RPM and 7) Signal Not Available (SNA). The diagnostic checks the signal availability by checking if the received value is not equal to the SNA default value.