Engine Controls - System & Component Tests - Gasoline: Introduction

NOTE: References to Econoline include Cutaway and RV Cutaway. References to F250-550 Super Duty Pickup include Cab & Chassis.

NOTE: Testing individual components does not isolate shorted or open circuits. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate shorted or open wiring harness. For identification of circuits and terminals referenced in test procedures, see WIRING DIAGRAMS .

Before testing separate components or systems, perform QUICK TEST procedures in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article. If no DTCs are present or only pass codes are found during self-diagnostics and symptom is present, proceed to TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article for diagnosis by symptom. If sent here from TROUBLE SHOOTING - NO CODES article, proceed with diagnosis in this article.

In many cases a circuit that is open, or shorted to ground or power can be at fault. Component replacement is only suggested after testing and passing circuits and control devices. A component test may direct you to a system test in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article to help avoid replacement of a good component. If the component can be tested properly on its own, it will be included here.