For 1990-2009 cars

Begin the system diagnosis with Diagnostic System Check - Vehicle . 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 - Vehicle , identifies the correct procedure for diagnosing the system and where the procedure is located.

#### Symptoms

When it has been determined through Diagnostic System Check - Vehicle , that no DTCs are present, begin symptom diagnosis by reviewing the Transmission Component and System Description . Reviewing Transmission Component and System Description . information enables you to understand the operation of the system. 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 . The Symptoms - Automatic Transmission provides common diagnostic categories which relate directly to diagnostic information or procedures.