Toyota Tundra Service Manual: Pressure Sensor Circuit (B1423/23)

DESCRIPTION

This DTC is output when refrigerant pressure is extremely low (196 kPa (2.0 kgf/cm2, 28 psi) or less) or extremely high (3140 kPa (32.0 kgf/cm2, 455 psi) or more). The pressure switch, which is installed on the pipe of the high pressure side to detect refrigerant pressure, outputs a refrigerant pressure signal to the air conditioning amplifier.

The air conditioning amplifier controls the compressor according to the sensor characteristic.

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 system.

DTC Code

DTC Detection Condition

Trouble Area

B1423/23

Open or short in pressure switch circuit

  • Air conditioning pressure switch
  • Harness or connector
  • Air conditioning amplifier

WIRING DIAGRAM

CAUTION / NOTICE / HINT

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 system.

PROCEDURE

1.

CHECK HARNESS OR CONNECTOR (AIR CONDITIONING PRESSURE SWITCH - AIR CONDITIONING AMPLIFIER AND BODY GROUND)

(a) Disconnect the A20 air conditioning pressure switch connector.

(b) Disconnect the J19 air conditioning amplifier connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard resistance:

Tester Connection

Condition

Specified Condition

A20-1 (+S) - J19-9 (PSW)

Always

Below 1 Ω

A20-1 (+S) or J19-9 (PSW) - Body ground

Always

10 kΩ or higher

A20-2 (-S) - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.

CHECK AIR CONDITIONING PRESSURE SWITCH

(a) Set the manifold gauge set.

(b) Disconnect the A20 air conditioning pressure switch connector.

(c) Run the engine at approximately 2000 rpm.

(d) Set the blower speed control switch to the HI position.

(e) Set the temperature control level to the MAX. COOL position.

(f) Turn the A/C switch ON.

(g) Check the switch operation.

(1) Connect the positive (+) lead from an ohmmeter to terminal 1 (+S) and the negative (-) lead to terminal 2 (-S).

(2) Measure the resistance between the terminals when refrigerant pressure is changed as shown in the illustration.

OK:

Resistance varies as shown in the illustration.

Result

Result

Proceed to

NG

A

OK (Checking from the PROBLEM SYMPTOMS TABLE)

B

OK (Checking from the DTC)

C

A

REPLACE AIR CONDITIONING PRESSURE SWITCH

B

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C

REPLACE AIR CONDITIONING AMPLIFIER

    Compressor Lock Sensor Circuit (B1422/22)

    Air Mix Damper Control Servo Motor Circuit (Passenger Side) (B1441/41)

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