October 30: LEMON manuals on a temporary server, it is slow and having issues, download the manuals you need! Later in November we will switch back to the fast server.

Diagnostic Circuit Check

Diagnostic Circuit Check determines if: 1) the ECM is operating and can recognize a fault, and 2) if any faults exist. This is the starting point for any diagnosis. If no faults are indicated, go to the Diesel Diagnostic Check (DDC) Tester Check.

Fig 1: Flow Chart, Diagnostic Circuit Check

Fig 2: Flow Chart, Diagnostic Circuit Check