2012 Jeep Wrangler JK Factory Service Manual 24 - Heating and Air Conditioning

TRANSDUCER, A/C Pressure

DESCRIPTION

DESCRIPTION

The A/C pressure transducer (1) is a switch that is installed on a fitting located on the either the A/C liquid line or the A/C discharge line, depending on engine application. An internally threaded fitting on the A/C pressure transducer connect to the externally threaded Schrader-type fitting on the refrigerant line. A rubber O-ring seals the connection between the A/C pressure transducer and the refrigerant line fitting. The A/C pressure transducer is connected to the vehicle electrical system by a molded plastic connector with three terminals.

OPERATION

OPERATION

The A/C pressure transducer monitors the pressures in the high side of the refrigerant system through its connection to a fitting on the refrigerant line. The A/C pressure transducer will change its internal resistance in response to the pressures it monitors. A Schrader-type valve in the discharge line fitting permits the A/C pressure transducer to be removed or installed without disturbing the refrigerant in the A/C system.

The Powertrain Control Module (PCM) provides a 5 volt reference signal and a sensor ground to the A/C pressure transducer, and then monitors the output voltage of the transducer on a sensor return circuit to determine refrigerant pressure. The PCM is programmed to respond to the A/C pressure transducer and other sensor inputs by controlling the operation of the A/C clutch and the radiator cooling fan to help optimize A/C system performance and to protect A/C system components from damage. The PCM will disengage the A/C clutch when high side pressure rises above 2971 kPa (431 psi) or falls below 206 kPa (30 psi). The A/C pressure transducer input to the PCM also prevents the A/C clutch from engaging when ambient temperatures are below about 1.0° C (50° F), due to the pressure/temperature relationship of the refrigerant. When the refrigerant pressure rises above 1655 kPa (240 psi), the PCM will actuate the cooling fan.

The A/C pressure transducer is diagnosed using a scan tool (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Diagnosis and Testing).

The A/C pressure transducer cannot be adjusted or repaired and must be replaced if inoperative or damaged.

REMOVAL

REMOVAL



NOTE:

It is not necessary to discharge the refrigerant system to replace the A/C pressure transducer.



NOTE:

Typical A/C pressure transducer and refrigerant line shown.

  1. Disconnect and isolate the negative battery cable.

    2.  
  2. Disconnect the wire harness connector (1) from the A/C pressure transducer (2).

    3.  
  3. Remove the A/C pressure transducer from the fitting (3) located on either the A/C liquid line or A/C discharge line, depending on engine application.

    4.  
  4. Remove and discard the O-ring seal (4).

    5.  

INSTALLATION

INSTALLATION



NOTE:

Use only the specified O-ring as it is made of special material for R-134a. Use only refrigerant oil of the type required for the A/C compressor.



NOTE:

Typical A/C pressure transducer and refrigerant line shown.

  1. Lubricate a new O-ring seal (4) with clean refrigerant oil and install it onto the refrigerant line fitting (3).

    2.  
  2. Install the A/C pressure transducer (2) onto either the A/C liquid line or A/C discharge line, depending on engine application. Tighten the A/C pressure transducer securely.

    3.  
  3. Connect the wire harness connector (1) to the A/C pressure transducer.

    4.  
  4. Reconnect the negative battery cable.

    5.