HVAC Control System - General Information

• Specifications
  • General Specifications Chart
• Description And Operation
  • Climate Control System
    • Climate Control System
    • Principles of Operation
      • Notes
      • Heat Transfer
      • Latent Heat of Vaporization
      • Relative Humidity
      • Effects of Pressure on Boiling or Condensation
      • Compressor Anti-Slugging Strategy
      • The Refrigerant Cycle
    • Climate Control System Operation
      • Electronic Manual Temperature Control System
      • Electronic Automatic Temperature Control System
      • Auxiliary Climate Control System
    • System Airflow Description - EMTC
      • Max A/C
      • Panel
      • Panel/Floor
      • Off
      • Floor
      • Floor/Defrost
      • Defrost
    • System Airflow Description - EATC
      • Auto
      • Off
      • Panel
      • Panel/Floor
      • Floor
      • Floor/Defrost
      • Defrost
• Diagnosis And Testing
  • Climate Control System
    • Notes
    • Special Tool(s)
    • Inspection and Verification
    • Electronic Automatic Temperature Control Module - Diagnostic Methods
      • Notes
      • Electronic Automatic Temperature Control Module On-Demand Self Test
      • Electronic Automatic Temperature Control Module - Retrieve Continuous DTCs
    • Diagnostic Trouble Code Index
      • Electronic Automatic Temperature Control (EATC) Module Diagnostic Trouble Code (DTC) Index
    • Symptom Chart
    • Connector Circuit Reference
    • Pinpoint Tests
      • Pinpoint Test A: DTC B1251 OR DTC B1253 - A/C In-Vehicle Temperature Sensor Open Circuit or Short to Ground
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test B: DTC B1255 OR DTC B1257 - A/C Ambient Temperature Sensor Open Circuit or Short to Ground
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test C: DTC B2796 or DTC B2795 - Solar Radiation Sensor Open Circuit or Short to Ground
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test D: DTC B1242 Air Inlet Door Short/Failure
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test E: Incorrect/Erratic Direction of Airflow From Outlet(s)
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test F: No Communication With The Electronic Automatic Temperature Control (EATC) Module
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test G: The EATC System is Inoperative, Intermittent or Incorrect Operation
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test H: Insufficient, Erratic or No Heat
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test I: The A/C Does Not Operate/Does Not Operate Correctly
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test J: The A/C Is Always On
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test K: Temperature Control Is Inoperative/Does Not Operate Correctly
        • Normal Operation
        • Door actuator feed A circuits
        • Door actuator feed B circuits
        • Door actuator return circuits
        • Door actuator reference circuits
        • Door actuator feedback circuits
        • Possible Causes
        • Testing
      • Pinpoint Test L: The Blower Motor Is Inoperative - EMTC
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test M: The Blower Motor Does Not Operate Correctly- EMTC
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test N: The Blower Motor Is Inoperative - EATC
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test O: The Blower Motor Does Not Operate Correctly - EATC
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test P: The Auxiliary Blower Motor Is Inoperative
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test Q: The Auxiliary Blower Motor Does Not Operate Correctly
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test R: The Auxiliary Temperature Control Only Is Inoperative/Does Not Operate Correctly
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test S: The Auxiliary Panel/Floor Control Only Is Inoperative/Does Not Operate Correctly
        • Normal Operation
        • Possible Causes
        • Testing
      • Pinpoint Test T: The Auxiliary Temperature/Panel/Floor and Blower Motor Control Is Inoperative/Does Not Operate Correctly
        • Normal Operation
        • Possible Causes
        • Testing
    • Component Tests
      • Blower Motor Resistor
      • Auxiliary Blower Motor Resistor
      • In-Vehicle Temperature Sensor
      • Ambient Temperature Sensor
      • Heater Core
      • Heater Core - Plugged
      • Heater Core - Pressure Test
      • Heater Core - Bench Test
      • Evaporator/Condenser Core - On-Vehicle Leak Test
      • A/C Compressor - External Leak Test
• General Procedures
  • Air Conditioning (A/C) System Check - Retail Procedure
    • Notes
    • Visual inspection
  • Air Conditioning Line (Peanut) Fitting
    • Disconnect
    • Connect
  • Air Conditioning (A/C) Clutch Air Gap Adjustment
  • Fluorescent Dye Leak Detection
    • Special Tool(s)
    • Fluorescent Dye Detection
    • Fluorescent Dye Injection - Using an A/C Refrigerant Center and Dye Injector
    • Fluorescent Dye Injection - Using a Dye Injector Loop Kit
  • Electronic Leak Detection
    • Special Tool(s)
    • Leak Detection
  • Air Conditioning (A/C) System Flushing
    • Special Tool(s)
    • Material
    • System Flushing
  • Air Conditioning (A/C) System Recovery, Evacuation and Charging
    • Special Tool(s)
    • Material
    • Refrigerant System Recovery
    • Refrigerant System Evacuation Using an R-134a Service Center
    • Refrigerant System Evacuation Using an R-134a Manifold Gauge Set
    • Refrigerant System Charging Using an R-134a Service Center
    • Refrigerant System Charging
  • Refrigerant Oil Adding
    • Special Tool(s)
    • Material
    • Refrigerant Oil Adding
    • Refrigerant Oil Adding for New A/C Compressor Installation
    • Refrigerant Oil Adding for New Suction Accumulator or Receiver/Drier Installation
    • Oil Injection Using a Dye/Lubricant Injector
  • Refrigerant Identification Testing
    • Special Tool(s)
    • Refrigerant Identification
    • Contaminated Refrigerant Handling
  • Air Conditioning (A/C) Odor Treatment
    • Special Tool(s)
    • Material
    • A/C Odor Treatment