Automatic Air Conditioning System

AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System): 23: Pressure Switch Circuit

DTC 23 - Pressure Switch Circuit

DESCRIPTION

The pressure switch sends the appropriate signals to the A/C amplifier when the A/C refrigerant pressure drops too low or rises too high. When the A/C amplifier receives these signals, it outputs signals through the A/C amplifier to turn the magnetic clutch relay off and turns the magneticic clutch off.









WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT REFRIGERANT PRESSURE
(a) Set the manifold gauge.
(b) Read the manifold gauge pressure when these conditions are established.
Test conditions:

- Temperature at the air inlet with the switch set at RECIRC is 30 to 35°C (86 to 95°F)
- Engine running at 1,500 rpm
- Blower speed control switch at "HI" position
- Temperature control dial at "COOL" position
- Air conditioning switch ON
- Fully open doors
Standard pressure:
Pressure on high pressure side
1.37 to 1.57 MPa (13.9 to 16.0 kgf/cm2, 198 to 228 psi)

HINT: If the refrigerant pressure is below 196 kPa (2.0 kgf/cm2, 28 psi), the refrigerant amount the air conditioning cycle may have decreased significantly for reasons such as a gas leakage.

NG -- INSPECT AND REPAIR AIR CONDITIONING CYCLE
OK -- Continue to next step.
2. CHECK AIR CONDITIONING OPERATION





(a) Disconnect the pressure switch connector.
(b) Connect terminals P2-1 and P2-4 of the connector of the pressure switch on the vehicle wire harness side using a service wire.
(c) Start the engine.
(d) Turn the air conditioning switch is on and check that the magnetic clutch is turned on.
(e) Check that the magnetic clutch is turned off when disconnecting terminals P2-1 and P2-4 (that are connected in the prior step).
OK:
Terminals P2-1 and P2-4 connected: magnetic clutch is on
Terminals P2-1 and P2-4 disconnected: magnetic clutch is off
NG -- CHECK HARNESS AND CONNECTOR (PRESSURE SWITCH - AIR CONDITIONING AMPLIFIER)
OK -- REPLACE PRESSURE SWITCH (COOLER CONDENSER ASSEMBLY)
3. CHECK HARNESS AND CONNECTOR (PRESSURE SWITCH - AIR CONDITIONING AMPLIFIER)





(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:





Result:





C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- REPAIR OR REPLACE HARNESS OR CONNECTOR