A/C Compressor - Operation
A/C COMPRESSOR - 5.7L HEV MODEL
The Denso ES34 Electric Air Compressor (EAC) (1) used on Hybrid Electric Vehicle (HEV) models is driven by an integral 3-phase Direct Current (DC) motor and lubricated by refrigerant oil that is circulated throughout the refrigerant system by the refrigerant.
The A/C compressor draws in low pressure refrigerant vapor from the A/C evaporator through the suction port, then compresses the refrigerant into a high pressure, high temperature refrigerant vapor, which is then pumped to the A/C condenser from the compressor discharge port.
The ES34 A/C compressor is controlled by the A/C-heater control in the instrument panel. The A/C compressor uses an inverter module (2) that converts the computer message from the A/C-heater control to the A/C compressor inverter module. The A/C compressor inverter module speeds up or slows down the electric drive motor, which increases or decreases the flow of refrigerant to match the A/C-heater control requirements necessary to meet the requested cabin temperature. The A/C compressor is mounted to the left side of the engine, below the exhaust manifold.
ES34 A/C compressor engagement criteria is as follows.
- Vehicle started with Ready Light on
- Ambient temperature reading on overhead console greater than 0° C (32° F)
- A/C refrigerant pressure greater than 2.5 Bar (36 psi)
- Propulsion system A/C request message active (indicating high volt system will allow compressor engagement)
The propulsion system A/C request message originates from the Hybrid Gateway Module (HGM) and is sent to the Front Control Module (FCM) over the Controller Area Network (CAN) C bus. The request message is then sent from the FCM to the A/C-heater control over the CAN B bus.
The A/C-heater control uses the following inputs to calculate a RPM request for the A/C compressor.
- Power limits from the HGM
- A/C pressure from the FCM
- A/C demand is calculated by humidity, ambient temperature, infrared and sun sensor data and customer temperature settings
A/C compressor command RPM and actual compressor RPM can be read using a scan tool via the A/C-heater control.
The EAC inverter module is diagnosed using a scan toolTesting and Inspection.
WARNING: Always follow approved service procedures to properly disconnect batteries and verify the absence of electrical power prior to servicing the A/C system on an HEV model. Failure to follow this warning may result in possible serious or fatal injury Procedures.
WARNING: The ES34 A/C compressor, DC motor and inverter module cannot be repaired or serviced separately and must be replaced as an assembly. There are no serviceable components located inside the ES34 A/C compressor. Failure to follow this warning may result in possible serious or fatal injury.
CAUTION: Be certain to adjust the refrigerant system oil level when servicing the A/C system or replacing an A/C compressor Refrigerant Oil Capacity . Failure to properly adjust the refrigerant oil level can prevent the A/C system from operating as designed and can cause serious A/C compressor damage.
CAUTION: Always use ND-11 POE refrigerant oil from Mopar(R) in an HEV model. Never use PAG oil in an HEV model. See A/C refrigerant oil for more information.
The ES34 A/C compressor, DC motor and inverter module cannot be repaired and must be replaced as an assembly if inoperative or damaged. If an internal failure of an A/C compressor has occurred, replace the A/C receiver/drier Front A/C Receiver Drier - Removal.