B1423

AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1423/23: Pressure Sensor Circuit
B1423/23 - Pressure Sensor Circuit

DESCRIPTION

This DTC is output when refrigerant pressure is extremely low (0.19 MPa (2.0 kgf/cm2, 28 psi) or less) or extremely high (3.14 MPa (32.0 kgf/cm2, 455 psi) or more). The pressure sensor, which is installed on the pipe of the high pressure side to detect refrigerant pressure, outputs the refrigerant pressure signal to the A/C amplifier. The A/C amplifier converts the signals to pressure according to the sensor characteristics to control the compressor.

HINT
Be sure to check the refrigerant volume first when this DTC is output because this DTC can also be output if there is no refrigerant in the cycle.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK REFRIGERANT





(a) Check the sight glass on the liquid pipe.

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





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





HINT
*: Bubbles in the sight glass with the vehicle interior above 35°C (95°F) can be considered normal if cooling is sufficient.

NG -- CHARGE REFRIGERANT
OK -- Continue to next step.

2. READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Select the item below in the Data List, and read the display on the Techstream.

Data List / Air Conditioner





OK:

The display is as specified in the normal condition.

Result





C -- REPLACE AIR CONDITIONING AMPLIFIER

B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.

3. CHECK WIRE HARNESS (PRESSURE SENSOR - A/C AMPLIFIER)





(a) Disconnect the B4 pressure sensor connector.

(b) Disconnect the K52 A/C amplifier connector.

(c) Measure the resistance of the wire harness side connectors.

Standard resistance:





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

4. CHECK AIR CONDITIONING AMPLIFIER





(a) Remove the A/C amplifier with its connectors still connected.

(b) Measure the resistance of the connector.

Standard resistance:





(c) Measure the voltage resistance of the connector.

Standard voltage:





NG -- REPLACE AIR CONDITIONING AMPLIFIER
OK -- Continue to next step.

5. CHECK PRESSURE SENSOR





(a) Install the manifold gauge set.

(b) Connect the three 1.5 V dry cell batteries' 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 PRESSURE SENSOR

OK -- REPLACE AIR CONDITIONING AMPLIFIER