Pressure Switch Circuit - Air Conditioning System

AIR CONDITIONING: AIR CONDITIONING SYSTEM: 23: Pressure Switch Circuit

DTC 23 - Pressure Switch Circuit

DESCRIPTION

The pressure switch sends 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 via the A/C amplifier to switch OFF the compressor relay and turn OFF the magnetic clutch.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT REFRIGERANT PRESSURE
(a) Set the manifold gauge Refrigerant.
(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 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 in the air conditioning cycle may have decreased significantly for reasons such as a gas leakage.

NG -- REPAIR OR REPLACE AIR CONDITIONING CYCLE
OK -- Continue to next step.

2. CHECK AIR CONDITIONING OPERATION




(a) Disconnect the pressure switch connector.
(b) Connect terminals 1 and 2 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 on and check that the magnetic clutch is turned on.
(e) Check that the magnetic clutch is turned off when disconnecting terminals 1 and 2 (that are connected in the prior step).
OK:
Terminals 1 and 2 connected
the compressor is operated
Terminals 1 and 2 disconnected
the compressor is not operated

NG -- CHECK HARNESS AND CONNECTOR (PRESSURE SWITCH - AIR CONDITIONING AMPLIFIER)
OK -- REPLACE PRESSURE SWITCH
3. CHECK HARNESS AND CONNECTOR (PRESSURE SWITCH - AIR CONDITIONING AMPLIFIER)
(a) Check for open and short circuit in the harness and the connector between the pressure switch and the A/C amplifier Electronic Circuit Inspection Procedure.

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

4. CHECK DTC
(a) Start up the DTC check mode.
(b) Check that DTC 23 is not output again.
Result:





C -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
B -- SYSTEM IS OK
A -- REPLACE AIR CONDITIONING AMPLIFIER