Natural Gas Vehicle

1. Verify customer's concern by operating the instrument cluster to duplicate the condition and by observing the indicators and gauges to determine if they are operating properly with the ignition switch:
- in RUN with the engine OFF.
- in START before the ignition switch is released.
- in RUN with the engine running.
2. Inspect to determine if any of the mechanical or electrical concerns apply:

VISUAL INSPECTION CHART

Mechanical
- Damaged fuel tank.
- Engine coolant level.
- Engine oil level.

Electrical
- Damaged Fuse(s) 8 (15 A), 18 (15 A), 15 (10 A).
- circuit wiring.
- Damaged switches or sensors.

3. If inspection reveals obvious concern(s) that can be readily identified, service as required.
4. If a concern remains after the inspection, connect the Rotunda New Generation Star (NGS) Tester 418-F048 (007-00500) or equivalent to the Data Link Connector (DLC) located beneath the instrument panel to perform DATA LINKS DIAGNOSTICS test. If the NGS responds with NO RESPONSE/NOT EQUIPPED for the Natural Gas Vehicle (NGV) Module, GO to Pinpoint Test A.

A: No Communication With the NGV Module

If the DATA LINK DIAGNOSTICS test is passed for the NGV Module retrieve continuous Diagnostic Trouble Code (DTCs) and execute Self Test Diagnostics for the NGV Module to retrieve current DTCs.
5. If self test is passed and no DTCs are retrieved, go to the Symptom Chart to continue diagnostics.

Natural Gas Vehicle (NGV)

6. If DTCs are retrieved, go to the Natural Gas Vehicle (NGV) Module Diagnostic Trouble Codes (DTCs) Index to continue diagnostics.

Natural Gas Vehicle (NGV) Diagnostic Trouble Code (DTC) Index

7. If the NGV Module cannot be accessed by the NGS, go to Pinpoint Test A.

A: No Communication With the NGV Module

Rotunda Service Bay Diagnostic System (SBDS (R)) 418-F001 (001-00001) may also be used to diagnose this system.