Engine Controls - System & Component Testing - CNG: Introduction

Before testing separate components or systems, follow proper workflow. See DIAGNOSTIC PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - RAM VAN article. If no Diagnostic Trouble Codes (DTC) are present and a no-start condition exists, proceed to NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - RAM VAN - CNG article. If no DTCs are present and a driveability condition exists, proceed to TROUBLE SHOOTING - NO CODES - RAM PICKUP & RAM VAN - CNG & GASOLINE article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).

NOTE: Testing of individual components does not isolate possible shorts or opens in wiring harness of electronically controlled systems. Perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance unless otherwise instructed in procedure. Use an ohmmeter to isolate wiring harness shorts or opens.