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Climate Control System -- Electric: Overview Ford Focus III

Automatic HVAC System 1 illustration ~1372 words

Overview

The Dual Automatic Temperature Control (DATC) system maintains the selected vehicle interior temperature by heating and/or cooling the air depending on the HVAC control panel selection.

  1. The driver may override the automatic mode of operation.
  2. The temperature control setting is the desired cabin air temperature.
  3. The blower motor control override buttons vary the blower motor speed.
  4. The driver side and passenger side temperature settings can be individually controlled.
  5. During A/C operation, the system reduces the relative humidity of the air inside the vehicle.

HEV is equipped with an Exhaust Manifold and Catalytic Converter Assembly with coolant passages to heat engine coolant more rapidly, speeding up passenger compartment heating in cold temperatures.

Scheme 6

Scheme 6: System Diagram

Normal Operation and Fault Conditions

The Air Conditioning Control Module (ACCM) requires an operating voltage between 9 and 16 volts. The Air Conditioning Control Module (ACCM) receives this voltage from the BJB . The Air Conditioning Control Module (ACCM) has a single ground circuit located in the engine compartment wiring harness. Excessive resistance or an open in one or more of these circuits, a discharged battery or an inoperative charging system results in the Air Conditioning Control Module (ACCM) setting a DTC .

DTCDescriptionFault Trigger Conditions
P0562:00System Voltage Low: No Sub Type InformationIf the Air Conditioning Control Module (ACCM) detects low voltage system voltage drops below 8.5 volts, this DTC sets after 5 seconds and the compressor motor is stopped.

DTC FAULT TRIGGER CONDITIONS

System Operation

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

Mode Door Actuator - Air Inlet Blend Door

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

During an actuator calibration cycle, the Heating, Ventilation, and Air Conditioning (HVAC) control module drives the air inlet blend door until the door reaches both internal stops in the Heating, Ventilation, and Air Conditioning (HVAC) case. If the air inlet mode door is temporarily obstructed or binding during a calibration cycle, the Heating, Ventilation, and Air Conditioning (HVAC) control module may interpret this as the actual end of travel for the door. When this condition occurs and the Heating, Ventilation, and Air Conditioning (HVAC) control module commands the actuator to its end of travel, the air intake may not be from the expected source.

DTCDescriptionFault Trigger Conditions
B1083:00Recirculation Damper Motor: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) and on-demand Diagnostic Trouble Code (DTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses no changes in the feedback circuit when motor movement is commanded.

DTC FAULT TRIGGER CONDITIONS

During an actuator calibration cycle, the Heating, Ventilation, and Air Conditioning (HVAC) control module drives the defrost vent/register blend door or the footwell vent/duct blend door until the door reaches the internal stops in the Heating, Ventilation, and Air Conditioning (HVAC) case. If either mode door is temporarily obstructed or binding during a calibration cycle, the Heating, Ventilation, and Air Conditioning (HVAC) control module may interpret this as the actual end of travel for the door. When this condition occurs and the Heating, Ventilation, and Air Conditioning (HVAC) control module commands the actuator to its end of travel, the airflow may not be from the expected outlets.

DTCDescriptionFault Trigger Conditions
B1085:00Defroster Damper Motor: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) and on-demand Diagnostic Trouble Code (DTC) sets in the Heating, Ventilation, and Air Conditioning (HVAC) control module.
B1086:00Air Distribution Damper Motor: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) and on-demand Diagnostic Trouble Code (DTC) sets in the Heating, Ventilation, and Air Conditioning (HVAC) control module.

DTC FAULT TRIGGER CONDITIONS

When the engine is at operating temperature hot coolant flows from the electric motor through the heater core and back to the electric motor. Correct coolant temperatures are critical for good heater performance.

Control System Logic

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

Controls and Compressor Cycling

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

A/C Low Pressure Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

A/C High Pressure Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

Evaporator Temperature Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

DTCDescriptionFault Trigger Conditions
B11EE:92A/C Compressor: Performance or Incorrect OperationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the ACCM detects the number of stops due to "software overcurrent" or "start failure" exceeds a specified value.

DTC FAULT TRIGGER CONDITIONS

Control System Logic

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

Controls and Compressor Cycling

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

A/C Low Pressure Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

A/C High Pressure Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

Evaporator Temperature Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

Control System Logic

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

Controls and Compressor Cycling

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

A/C Low Pressure Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION

A/C High Pressure Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

Evaporator Temperature Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

Temperature Blend Door Actuator - LH

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

During an actuator calibration cycle, the Heating, Ventilation, and Air Conditioning (HVAC) control module drives the temperature blend door until the door reaches both internal stops in the Heating, Ventilation, and Air Conditioning (HVAC) case. If the temperature blend door is temporarily obstructed or binding during a calibration cycle, the Heating, Ventilation, and Air Conditioning (HVAC) control module may interpret this as the actual end of travel for the door. When this condition occurs and the Heating, Ventilation, and Air Conditioning (HVAC) control module commands the actuator to its end of travel, the airflow may not be the expected temperature.

DTCDescriptionFault Trigger Conditions
B1081:00Left Temperature Damper Motor: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) and on-demand Diagnostic Trouble Code (DTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses no changes in the feedback circuit when motor movement is commanded and no motor electrical Diagnostic Trouble Codes (DTCs) are present.

DTC FAULT TRIGGER CONDITIONS

Temperature Blend Door Actuator - RH

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

During an actuator calibration cycle, the Heating, Ventilation, and Air Conditioning (HVAC) control module drives the temperature blend door until the door reaches both internal stops in the Heating, Ventilation, and Air Conditioning (HVAC) case. If the temperature blend door is temporarily obstructed or binding during a calibration cycle, the Heating, Ventilation, and Air Conditioning (HVAC) control module may interpret this as the actual end of travel for the door. When this condition occurs and the Heating, Ventilation, and Air Conditioning (HVAC) control module commands the actuator to its end of travel, the airflow may not be the expected temperature.

DTCDescriptionFault Trigger Conditions
B1082:00Right Temperature Damper Motor: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) and on-demand Diagnostic Trouble Code (DTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses no changes in the feedback circuit when motor movement is commanded and no motor electrical Diagnostic Trouble Codes (DTCs) are present.

DTC FAULT TRIGGER CONDITIONS

Voltage is supplied to the blower motor relay from the BJB . When the blower motor relay coil receives a ground from the Body Control Module (BCM), the relay coil is energized and voltage is delivered to the blower motor control module. Power and ground for the blower motor is provided by the blower motor speed control. The Heating, Ventilation, and Air Conditioning (HVAC) control module sends a Pulse Width Modulated (PWM) signal to the blower motor speed control to control the blower speed.

DTCDescriptionFault Trigger Conditions
B10AF:13Blower Fan Relay: Circuit OpenThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Body Control Module (BCM) senses no voltage on the relay coil ground circuit when the module is grounding the circuit.
B10AF:19Blower Fan Relay: Circuit Current Above ThresholdThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Body Control Module (BCM) senses excessive voltage on the relay coil ground circuit when the module is grounding the circuit.
B10B9:00Blower Control: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) and on-demand Diagnostic Trouble Code (DTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses no voltage on the blower motor control Pulse Width Modulated (PWM) circuit.

DTC FAULT TRIGGER CONDITIONS

Voltage is supplied to the blower motor relay from the BJB . When the blower motor relay coil receives a ground from the Body Control Module (BCM), the relay coil is energized and voltage is delivered to the blower motor control module. Power and ground for the blower motor is provided by the blower motor speed control. The Heating, Ventilation, and Air Conditioning (HVAC) control module sends a Pulse Width Modulated (PWM) signal to the blower motor speed control to control the blower speed.

DTCDescriptionFault Trigger Conditions
B10AF:11Blower Fan Relay: Circuit Short To GroundThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Body Control Module (BCM) senses a path to ground on the blower motor control circuit.
B10B9:00Blower Control: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) and on-demand Diagnostic Trouble Code (DTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses no voltage on the blower motor control Pulse Width Modulated (PWM) circuit.

DTC FAULT TRIGGER CONDITIONS

The 4 air discharge temperature sensors contain a thermistor. The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls, the resistance rises.

DTCDescriptionFault Trigger Conditions
B10B3:00Right Panel Air Discharge Temperature: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses erratic voltages from the right panel air discharge temperature sensor.
B10B4:00Right Floor Air Discharge Temperature: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses erratic voltages from the right floor air discharge temperature sensor.
B10B5:00Left Panel Air Discharge Temperature: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses erratic voltages from the left panel air discharge temperature sensor.
B10B6:00Left Floor Air Discharge Temperature: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses erratic voltages from the left floor air discharge temperature sensor.

DTC FAULT TRIGGER CONDITIONS

In-Vehicle Temperature and Humidity Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

DTCDescriptionFault Trigger Conditions
B1A61:00Cabin Temperature Sensor: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses erratic voltages from the cabin temperature sensor.
B105A:00Cabin Temperature Sensor Fan: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses no voltage or expected voltage on the circuit for the cabin temperature sensor fan.

DTC FAULT TRIGGER CONDITIONS

Sunload Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

DTCDescriptionFault Trigger Conditions
B1A63:00Right Solar Sensor: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses lower than expected voltage on an open, short to voltage or short to ground from the light sensor input circuit.
B1A64:00Left Solar Sensor: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses an open, short to voltage or short to ground from the light sensor input circuit.

DTC FAULT TRIGGER CONDITIONS

The Heating, Ventilation, and Air Conditioning (HVAC) control module requires an operating voltage that is between 9 and 16 volts. The Heating, Ventilation, and Air Conditioning (HVAC) control module receives this voltage from the BJB . The Heating, Ventilation, and Air Conditioning (HVAC) control module has a single ground circuit located in the engine compartment wiring harness. Excessive resistance or an open in one or more of these circuits, a discharged battery or an inoperative charging system will result in the Heating, Ventilation, and Air Conditioning (HVAC) control module setting a DTC .

DTCDescriptionFault Trigger Conditions
U3006:16Control Module Input Power "A": Circuit Voltage Below ThresholdThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses lower than expected voltage.
U3006:17Control Module Input Power "A": Circuit Voltage Above ThresholdThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Heating, Ventilation, and Air Conditioning (HVAC) control module senses greater than expected voltage.

DTC FAULT TRIGGER CONDITIONS

Control System Logic

REFER to: CLIMATE CONTROL SYSTEM - COMPONENT LOCATION .

DTCDescriptionFault Trigger Conditions
U0155:00Lost Communication With Instrument Panel Cluster (IPC) Control Module: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets in the Heating, Ventilation, and Air Conditioning (HVAC) control module if data messages received from the IPC over the Controller Area Network (CAN) are missing for 5 seconds or more.

DTC FAULT TRIGGER CONDITIONS

Evaporator Temperature Sensor

REFER to: CLIMATE CONTROL SYSTEM - SYSTEM OPERATION AND COMPONENT DESCRIPTION .

DTCDescriptionFault Trigger Conditions
B1B71:21Evaporator Temperature Sensor: Signal Amplitude < MinimumThis Continuous Memory Diagnostic Trouble Code (CMDTC) and on-demand Diagnostic Trouble Code (DTC) sets when the Body Control Module (BCM) senses lower than expected voltage from the evaporator temperature sensor.
B1B71:22Evaporator Temperature Sensor: Signal Amplitude > MaximumThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets when the Body Control Module (BCM) senses greater than expected voltage from the evaporator temperature sensor.
B1B71:2FEvaporator Temperature Sensor: Signal ErraticThis on-demand Diagnostic Trouble Code (DTC) sets when the Body Control Module (BCM) senses erratic voltages from the evaporator temperature sensor.

DTC FAULT TRIGGER CONDITIONS

Control System Logic

REFER to: CLIMATE CONTROL SYSTEM - COMPONENT LOCATION .

DTCDescriptionFault Trigger Conditions
U0293:00Lost Communication With Hybrid/EV Powertrain Control Module: No Sub Type InformationThis Continuous Memory Diagnostic Trouble Code (CMDTC) sets in the Air Conditioning Control Module (ACCM) if data messages received from the Powertrain Control Module over the High Speed Controller Area Network (HS-CAN) are missing for 5 seconds or more.

DTC FAULT TRIGGER CONDITIONS