Engine Controls - System & Component Tests - CNG: Introduction: Notes
NOTE:
References to Econoline include Cutaway and RV Cutaway models.
WARNING:
Before performing any tests or diagnostics on CNG or LPG components or systems, read all cautions and warnings in CNG/LPG SAFETY PRECAUTIONS article in GENERAL INFORMATION.
NOTE:
System and component testing included in this article is for CNG fuel systems only. For gasoline fuel system and component testing, see SYSTEM & COMPONENT TESTING - GASOLINE
article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) when a malfunction occurs, check for Powertrain Control Module (PCM) DTCs prior to testing an individual system or component. Perform QUICK TEST
procedures in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article. If no DTCs are present, perform SYMPTOM DIAGNOSIS
under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article to diagnose driveability problems existing when a hard fault code is not present.
NOTE:
Testing individual components does not isolate short 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 DVOM to isolate shorted or open wiring harness. For identification of circuits and terminals referenced in test procedures, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL.