Low Pressure Sensor Circuit

AIR CONDITIONING: AIR CONDITIONING SYSTEM: Low Pressure Sensor Circuit
- Low Pressure Sensor Circuit

DESCRIPTION

The low pressure sensor reduces the capacity of the compressor when the compressor is operating at high speed. This sensor monitors the pressure on the low pressure side at terminal CUT+ and sends a signal to terminal PSW of the A/C amplifier, which increases the accuracy of compressor control.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK REFRIGERANT PRESSURE

(a) Check the sight glass of the cooler unit refrigerant liquid pipe.





(1) Prepare the vehicle according to the chart below.





(2) Compare the sight glass to the following chart.





*: Bubbles in the sight glass with the vehicle interior temperature above 35°C (95°F) can be considered normal if cooling is sufficient.
NG -- CHARGE REFRIGERANT
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - LOW PRESSURE SENSOR)

(a) Disconnect the pressure sensor connector.





(b) Disconnect the A/C amplifier connector.

(c) Measure the resistance according to the value(s) in the table below.

:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

3. INSPECT LOW PRESSURE SENSOR

(a) Install the manifold gauge set Refrigerant.

(b) Connect the three 1.5 V dry cell battery's positive (+) lead to terminal 3 and the negative (-) lead to terminal 1. Then connect the voltmeter's positive (+) lead to terminal 2 and the negative (-) lead to terminal 1. Measure the voltage.





OK:

The voltage changes according to refrigerant pressure, as shown in the graph.

NG -- REPLACE LOW PRESSURE SENSOR

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE