B1423

AIR CONDITIONING SYSTEM: B1423/23: Pressure Sensor Circuit

DTC B1423/23 - Pressure Sensor Circuit

DESCRIPTION





The A/C pressure switch to detect the refrigerant pressure is located in the sight glass side of the pipe on the high-pressure side. This DTC is output when the refrigerant pressure is either significantly low (below 196 kPa (2.0 kgf/cm2, 28 psi) or significantly high (over 3,140 kPa (32.0 kgf/cm2, 455 psi). Then the A/C pressure switch has built-in switches to detect high and low pressure and is turned off when either of them is determined to be detective. The A/C amplifier assembly continuously monitors the pressure switch signal after the ignition switch is turned on. It stops compressor control and outputs the DTC when it detects the signal indicating that the switch is turned off.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT REFRIGERANT PRESSURE
(a) Set the manifold gauge. Refrigerant

(b) Read the manifold gauge pressure when the following conditions are established.

- Temperature at the air inlet with the switch set at RECIRCULATION is 30 to 35°C (86 to 95°F)
- Ignition switch is ON.
- Blower speed control switch is at "HI" position
- Temperature control dial is at "COOL" position
- Air conditioning switch is ON
- Doors are fully open

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 -- CHECK AND REPLACE AIR CONDITIONING CYCLE
OK -- Continue to next step.
2. CHECK AIR CONDITIONING OPERATION





(a) Disconnect the connector from the A/C pressure switch.
(b) Connect the terminals 1 and 4 of the connector of the pressure switch on the vehicle wire harness side using a service wire.
(c) Turn the ignition switch ON.
(d) Turn the air conditioning switch ON and check that the compressor is operated.
(e) Check that the compressor is not operated when terminals 1 and 4 (that were connected in the prior step) are disconnected.
OK:
Terminals 1 and 4 connected: the compressor is operated
Terminals 1 and 4 disconnected: the compressor is not operated
(f) Check that the electrical fan is operated when disconnecting terminals 2 and 3 (that were connected in the prior step).
OK:
Terminals 2 and 3 connected: the electrical fan is operated
Terminals 2 and 3 disconnected: the electrical fan is not operated
NG -- CHECK HARNESS AND CONNECTOR (A/C PRESSURE SWITCH - HYBRID VEHICLE CONTROL ECU)
OK -- REPLACE A/C PRESSURE SWITCH
3. CHECK HARNESS AND CONNECTOR (A/C PRESSURE SWITCH - HYBRID VEHICLE CONTROL ECU)





(a) Disconnect the connectors from the A/C pressure switch and hybrid vehicle control ECU.
(b) Measure the resistance according to the value(s) in the table below.
Resistance:






Result:






C -- REPLACE HYBRID VEHICLE CONTROL ECU
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- REPAIR OR REPLACE HARNESS OR CONNECTOR