Theory Of Operation

WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

There Are Two Tests Performed By This Diagnostic:

The First Test Monitors The Control System To Ensure The Fueling Output Is Consistent Based On The Operating Conditions. The Powertrain Control Module PCM Will Light The Etc Lamp Immediately After The Diagnostic Runs And Fail. During This Time The Customer May Experience An Engine Running Rough Condition. The PCM Will Turn Off The Etc Lamp Once The Diagnostic Passes In One Drive Cycle.

The Second Test Checks The Internal PCM Fuel System Diagnostic, Called Application Specific Integrated Circuit (Asic), For Proper Operation By Intentionally Inducing A Failure And Looking For The Proper PCM Response. At Key Off, The Diagnostic Overwrites Injector On Time And Falsely Cycles The Injectors. If The Internal PCM Protection Chip (Asic) Detects The Firing And Sets An Error Then The Diagnostic Passes. This Diagnostic Initially Only Runs At Key Off. If The Diagnostic Failed At The Last Key Off Cycle, Then It Will Also Run At The Next Cranking Event. If The Driver Stalls The Engine (Manual Transmission Only) At The Same Moment That The Key Is Turned Off This Diagnostic Could Fail. When The Diagnostic Fails, The PCM Will Flash The Etc Lamp.