Begin the system diagnosis with Diagnostic System Check - Engine Controls in Engine Controls - 6.6L (LB7) or Diagnostic System Check - Engine Controls in Engine Controls - 8.1L. The Diagnostic System Check provides the following information:
| • | The identification of the control modules which commands the system |
| • | The ability of the control modules to communicate through the serial data circuit |
| • | The identification and status of stored diagnostic trouble codes (DTCs). |
The use of Diagnostic System Check - Engine Controls in Engine Controls - 6.6L (LB7) or Diagnostic System Check - Engine Controls in Engine Controls - 8.1L identifies the correct procedure for diagnosing the system and where the procedure is located.
Symptoms
When it has been determined through Diagnostic System Check - Engine Controls in Engine Controls - 6.6L (LB7) or Diagnostic System Check - Engine Controls in Engine Controls - 8.1 L that no DTCs are present, begin symptom diagnosis by reviewing the Functional Test . This helps you determine if the condition described by the customer is normal or if a malfunction exists. If it is determined that a malfunction exists, identify the concern by referring to the Symptoms - Automatic Transmission table. The Symptoms - Automatic Transmission table provides common diagnostic categories which relate directly to diagnostic information or procedures.
