Dtc B1423/23 Pressure Switch Circuit

Heater & Air Conditioning System. Lexus Gs430, Gs300. Uzs190 Grs190
Air Conditioning. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK REFRIGERANT

READ VALUE OF INTELLIGENT TESTER

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

CHECK AIR CONDITIONING AMPLIFIER

INSPECT PRESSURE SENSOR

DTC B1423/23 Pressure Switch 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.

DTC No.
DTC Detection Condition
Trouble Area
B1423/23
Open or short in pressure switch circuit
  1. Pressure sensor
  2. Harness and connector between pressure sensor and A/C amplifier
  3. Refrigerant pipe line
  4. A/C amplifier

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1423/23 Pressure Switch Circuit


INSPECTION PROCEDURE

1.CHECK REFRIGERANT


    Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1423/23 Pressure Switch Circuit

  1. Check the sight glass of the cooler unit refrigerant liquid pipe.

    1. Prepare the vehicle according to the chart below.

      Item
      		Condition
      Vehicle Doors
      		Fully open
      Temperature Setting
      		MAX COLD
      Blower Speed
      		HI
      A/C
      		ON

    2. Compare the sight glass to the following chart.


Item
Symptom
Amount of Refrigerant
Corrective Actions
1
Bubbles visible
Insufficient*
  1. Check for gas leakage and repair if necessary
  2. Add refrigerant until bubbles disappear
2
No bubbles visible
Empty, insufficient or excessive
Refer to 3 and 4
3
No temperature difference between compressor inlet and outlet
Empty or nearly empty
  1. Check for gas leakage with gas leak detector and repair if necessary
  2. Evacuate A/C system and recharge proper amount of refrigerant
4
Considerable temperature difference between compressor inlet and outlet
Proper or excessive
Refer to 5 and 6
5
Immediately after air conditioning is turned OFF, refrigerant clears
Excessive
  1. Discharge refrigerant
  2. Evacuate A/C system and recharge proper amount of refrigerant
6
Immediately after air conditioning is turned OFF, refrigerant foams and then becomes clear
Proper
-
*: 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


2.READ VALUE OF INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and push the intelligent tester main switch on.

  1. Select the item below in the Data List, and read the display on the intelligent tester.


A/C amplifier:
Item
Measure Item / Display
(Range)
Normal Condition
Diagnostic Note
Regulator Pressure Sensor
(Reg Press Sens)
Regulator Pressure Sensor /
Min.: 0, Max.: 255
Actual regulator pressure is displayed
-
Regulator Control Current
(Reg Ctrl Currnt)
Regulator Control Current /
Min.: 0 A, Max.: 255 A
-
-
OK:
The display is as specified in the normal condition.

NG
A
OK (Checking from the PROBLEM SYMPTOMS TABLE)
B
OK (Checking from the DTC)
C


B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER
A


3.CHECK WIRE HARNESS (PRESSURE SENSOR - A/C AMPLIFIER)
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1423/23 Pressure Switch Circuit

  1. Disconnect the B4 pressure sensor connector.

  1. Disconnect the L52 A/C amplifier connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    B4-2 (PR) - L52-13 (PRE)
    		Always
    		Below 1 Ω
    B4-3 (+) - L52-26 (S5-2)
    		Always
    		Below 1 Ω
    B4-1 (-) - L52-38 (SG-2)
    		Always
    		Below 1 Ω
    L52-13 (PRE) - Body ground
    		Always
    		10 kΩ or higher
    L52-26 (S5-2) - Body ground
    		Always
    		10 kΩ or higher
    L52-38 (SG-2) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


4.CHECK AIR CONDITIONING AMPLIFIER
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1423/23 Pressure Switch Circuit

  1. Remove the A/C amplifier with its connectors still connected.

  1. Measure the resistance of the connector.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    L52-38 (SG-2) - Body ground
    		Always
    		Below 1 Ω

  1. Measure the voltage of the connector.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    L52-26 (S5-2) - Body ground
    		Engine switch on (IG)
    		10 to 14 V
    Engine switch off
    		Below 1 V


NG
REPLACE AIR CONDITIONING AMPLIFIER
OK


5.INSPECT PRESSURE SENSOR
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1423/23 Pressure Switch Circuit

  1. Install the manifold gauge set.

  1. 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