Chrysler Sebring, Stratus sedan, Sebring Convertible. Manual - part 731
A/C PRESSURE TRANSDUCER
DESCRIPTION
The A/C pressure transducer (Fig. 25) is a switch
that is installed on a fitting located on the A/C dis-
charge line. An internally threaded fitting on the
transducer connects it to the externally threaded
Schrader-type fitting on the A/C discharge line. A
rubber O-ring seals the connection between the
transducer and the discharge line fitting. The A/C
pressure transducer is connected to the vehicle elec-
trical system by a molded plastic connector with
three terminals.
OPERATION
The A/C pressure transducer monitors the pres-
sures in the high side of the refrigerant system
through its connection to a fitting on the A/C dis-
charge 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 refriger-
ant in the A/C system.
The powertrain control module (PCM) provides a
five volt reference signal and a sensor ground to the
A/C pressure transducer, then monitors the output
voltage of the A/C pressure transducer on a sensor
return circuit to determine refrigerant pressure. The
PCM is programmed to respond to this and other
sensor inputs by controlling the operation of the A/C
compressor clutch and the radiator cooling fan to
help optimize A/C system performance and to protect
the system components from damage. The PCM will
disengage the A/C compressor clutch when high side
pressure rises above 2971 kPa (431 psi) or falls below
206 kPa (30 psi). The A/C pressure transducer input
will also disengage the A/C compressor clutch when
ambient temperatures are below about 10° C (50° F)
due to the pressure/temperature relationship of the
refrigerant.
The A/C pressure transducer is diagnosed using a
DRBIII
t scan tool. Refer to the appropriate diagnos-
tic information.
The A/C pressure transducer cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
DIAGNOSIS AND TESTING
A/C PRESSURE TRANSDUCER
The A/C pressure transducer is tested using a
DRBIII
t scan tool. Refer to the appropriate diagnos-
tic information. Before testing the A/C pressure
transducer, be certain that the transducer wire har-
ness connection is clean of corrosion and properly
connected. For the A/C to operate, an A/C pressure
transducer voltage reading between 0.451 and 4.519
volts is required. Voltages outside this range indicate
a low or high refrigerant system pressure condition
to the powertrain control module (PCM). The PCM is
programmed to respond to a low or high refrigerant
system pressure by suppressing operation of the A/C
compressor. Refer to the A/C Pressure Transducer
Voltage chart for the possible conditions indicated by
the transducer voltage reading.
A/C PRESSURE TRANSDUCER VOLTAGE
Voltage
Possible Indication
0.0
1. No sensor supply voltage from
PCM.
2. Shorted sensor circuit.
3. Faulty transducer.
0.150 TO 0.450
1. Ambient temperature below
10° C (50° F).
2. Low refrigerant system
pressure.
0.451 TO 4.519
1. Normal refrigerant system
pressure.
4.520 TO 4.850
1. High refrigerant system
pressure.
5.0
1. Open sensor circuit.
2. Faulty transducer.
Fig. 25 A/C Pressure Transducer
1 - A/C PRESSURE TRANSDUCER
JR
CONTROLS
24 - 23