Important Preliminary Checks
Important Preliminary Checks
| Action
|
Before Performing Symptom Diagnosis
| Before performing Symptom based diagnosis you must perform the
Diagnostic System Check - Alternative Fuels (Engine Controls)
.
The System Check will determine the following:
| • | PCM and the MIL are operating correctly. |
| • | There are no DTCs stored. |
| • | Scan tool data is within normal operating range. |
Several of the Symptom diagnostic tables require that a Visual and Physical
Check be performed. Always perform a Visual and Physical Check before using a Symptom
diagnostic table.
|
Visual and Physical Checks
|
| • | Inspect the powertrain control module (PCM) ground connections for being
clean, tight and in the correct location. |
| • | Inspect the PCM for the correct CNG calibration. Program the PCM if necessary. |
| • | Inspect the vacuum hoses for leaks, restrictions and proper connection
as shown on the vehicle emission control information (VECI) label. |
| • | Inspect for any type of fuel leak or fuel line restriction. |
| • | Inspect for air leaks at all areas of the intake manifold sealing surfaces. |
| • | Inspect the ignition wires for the following conditions: |
| • | Inspect vehicle wiring for the following: |
|
Symptoms
|
- Verify the customer concern.
- Locate the Symptom table that indicates the customers concern.
- Test or Inspect for the items indicated for that symptom.
The following Symptom tables are located in this section:
|
