The Heating, Ventilation and Air Conditioning (HVAC) system is divided into two sections. The first, Heating, Ventilation and Air Conditioning, it has all of the replacement procedures that pertain to the HVAC components or functions that are associated with an automatic control system. The second, HVAC Systems-Automatic, has all of the diagnostic procedures specific to the automatic control system.
For systems with DTCs, begin the system diagnosis with the following procedures: Diagnostic System Check - HVAC Systems - Automatic in HVAC Systems-Automatic
The Diagnostic System Check will provide the following information:
| • | The identification of the control modules which command the system. |
| • | The ability of the control modules to communicate through the class 2 serial data circuit. |
The use of the Diagnostic System Check will identify and lead the technician to the correct diagnostic procedure.
Review the Automatic HVAC Description and Operation to help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the Description and Operation information will also help you determine if the condition described by the customer is normal operation. The HVAC Description and Operation information is divided into:
