Introduction

This vehicle was designed to operate exclusively on Compressed Natural Gas (CNG). Compressed Natural Gas is made up primarily of Methane and is in a gaseous state at all times.

Please follow the recommendations below when choosing your diagnostic path.

1. First make sure the DRB III is communicating with the appropriate modules; ie., if the DRB III displays a "No Response" condition, you must diagnose this first before proceeding.
2. Read DTC's (diagnostic trouble codes) with the DRB III.
3. If no DTC's are present, identify the customer complaint.
4. Once the DTC or customer complaint is identified, locate the matching test in the Table of Contents and begin to diagnose the symptom.

An asterisk placed before the symptom description indicated a customer complaint.

When repairs are required, refer to the proper removal and repair procedure.

Diagnostic procedures change every year. New diagnostic systems may be added; carryover systems may be enhanced. READ THIS SECTION BEFORE TRYING TO DIAGNOSE A VEHICLE CODE. It is recommended that you review the entire section to become familiar with all new and changed diagnostic procedures.