Toyota Venza: Pressure Sensor Circuit (B1423/23)

DESCRIPTION

This DTC is output when refrigerant pressure on the high pressure side is extremely low (190 kPa (1.9 kgf/cm2, 28 psi) or less) or extremely high (3140 kPa (32.0 kgf/cm2, 455 psi) or more). The A/C pressure sensor is installed on the high pressure line. It detects refrigerant pressure to output a refrigerant pressure signal to the A/C amplifier. The A/C amplifier converts this signal to a pressure value according to the sensor characteristics to control the compressor.

DTC No.	DTC Detection Condition	Trouble Area
B1423/23	Open or short in pressure sensor circuit Refrigerant pressure on the high pressure line is extremely low (190 kPa (1.9 kgf/cm2, 28 psi) or less) or extremely high (3140 kPa (32.0 kgf/cm2, 455 psi) or more).	A/C pressure sensor Harness or connector between A/C pressure sensor and A/C amplifier A/C amplifier Expansion valve (blocked, stuck) Condenser (blocked, deterioration of cooling capacity due to dirt) Cooler dryer (moisture in the refrigerant cycle cannot be absorbed) Cooling fan system (condenser cannot be cooled down) A/C system (leaks, blocked)

WIRING DIAGRAM

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

(a) Disconnect the A/C pressure sensor connector.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A39-3 (+) - Body ground	Ignition switch ON	4.75 to 5.25 V

Text in Illustration

*1	Front view of wire harness connector (to A/C Pressure Sensor)

NG

GO TO STEP 5

OK

2.	CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)

(a) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition A39-1 (-) - Body ground Always Below 1 Ω Text in Illustration *1 Front view of wire harness connector (to A/C Pressure Sensor)

NG

GO TO STEP 6

OK

3.	INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)

(a) Reconnect the A/C pressure sensor connector.

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

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
D47-9 (PRE) - Body ground	Ignition switch ON (A/C: off)	0.73 to 4.84 V

HINT:

If the voltage is not as specified, there may be a malfunction in the A/C amplifier, A/C pressure sensor or wire harness. It is also possible that the amount of refrigerant may not be appropriate.

Text in Illustration

*1	Component with harness connected (A/C Amplifier)

NG

GO TO STEP 7

OK

4.	INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)

(a) Measure the voltage when the following conditions are satisfied.

Item	Condition
Vehicle Doors	Fully open
Temperature Setting	MAX COLD
Blower Speed	HI
A/C Switch	on
R/F Switch	RECIRCULATION
Interior Temperature	25 to 35°C (77 to 95°F)
Engine Speed	2000 rpm

HINT:

When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from the ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

(1) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Condition Specified Condition D47-9 (PRE) - Body ground Ignition switch ON (A/C: on) 0.73 to 4.84 V Result: Result Proceed to OK (When troubleshooting according to the DTC) A OK (When troubleshooting according to Problem Symptoms Table) B NG C Text in Illustration *1 Component with harness connected (A/C Amplifier)

A

REPLACE A/C AMPLIFIER

B

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

C

GO TO STEP 13

5.	CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR)

(a) Disconnect the A/C amplifier connector.

(b) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition A39-3 (+) - D47-10 (S5-3) Always Below 1 Ω D47-10 (S5-3) - Body ground Always 10 kΩ or higher Text in Illustration *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Pressure Sensor)

OK

REPLACE A/C AMPLIFIER

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR)

(a) Disconnect the A/C amplifier connector.

(b) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition A39-1 (-) - D47-13 (GND) Always Below 1 Ω D47-13 (GND) - Body ground Always 10 kΩ or higher Text in Illustration *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Pressure Sensor)

OK

REPLACE A/C AMPLIFIER

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

7.	CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR)

(a) Disconnect the A/C amplifier connector.

(b) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition A39-2 (PR) - D47-9 (PRE) Always Below 1 Ω D47-9 (PRE) - Body ground Always 10 kΩ or higher Text in Illustration *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Pressure Sensor)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8.	CHECK FOR A/C SYSTEM LEAK

(a) Install the manifold gauge set.

(b) Recover the refrigerant from the A/C system using a refrigerant recovery unit.

(c) Evacuate the A/C system and check that vacuum can be maintained.

OK:

Vacuum can be maintained in the A/C system.

HINT:

If vacuum cannot be maintained in the A/C system, there may be a refrigerant leak. In this case, it is necessary to repair or replace the leaking part of the A/C system.

NG

GO TO STEP 12

OK

9.	CHARGE REFRIGERANT

(a) Add an appropriate amount of refrigerant (See page ).

NEXT

10.	RECHECK DTC

(a) Recheck for the DTC when the following conditions are satisfied.

Item	Condition
Vehicle Doors	Fully open
Temperature Setting	MAX COLD
Blower Speed	HI
A/C Switch	on
R/F Switch	RECIRCULATION
Interior Temperature	25 to 35°C (77 to 95°F)
Engine Speed	2000 rpm

NOTICE:

If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while.

HINT:

When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from the ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

Result	Proceed to
DTC B1423/23 is output	A
DTC B1423/23 is not output	B

NOTICE:

If the DTC was set due to an insufficient or excessive amount of refrigerant, the problem may have been solved after performing the previous step. However, the root cause of insufficient refrigerant may be refrigerant leaks. The root cause of excessive refrigerant may be adding refrigerant when the level was insufficient. Therefore, identify and repair any refrigerant leaks as necessary.

B

END

A

11.	INSPECT A/C PRESSURE SENSOR

(a) Install the manifold gauge set.

(b) Reconnect the A/C pressure sensor connector.

(c) Turn the ignition switch to ON.

(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Condition	Specified Condition
D47-9 (PRE) - D47-13 (GND)	Refrigerant pressure: Normal pressure (less than 3187 kPa (32.5 kgf/cm2, 462 psi) and more than 390 kPa (4.0 kgf/cm2, 57 psi))	1.0 to 4.912 V

Text in Illustration

*1	Component with harness connected (A/C Amplifier)

OK

REPLACE A/C AMPLIFIER

NG

GO TO STEP 19

12.	REPAIR A/C SYSTEM LEAK

(a) Identify the area where refrigerant leaks from (See page ).

(b) Repair the identified area of the A/C system.

(c) Evacuate the A/C system.

NEXT

CHARGE REFRIGERANT

13.	INSPECT COOLING FAN SYSTEM

(a) Check that the cooling fan(s) operates normally.

HINT:

Refer to Cooling Fan Circuit (See page ).

NG

REPAIR COOLING FAN SYSTEM

OK

14.	CHARGE REFRIGERANT

(a) Use a refrigerant recovery unit to recover refrigerant.

(b) Evacuate the A/C system.

(c) Add an appropriate amount of refrigerant (See page ).

HINT:

If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system will freeze in the expansion valve, blocking the flow on the high pressure side. Therefore, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and check for DTCs.

NEXT

15.	RECHECK DTC

(a) Recheck for the DTC when the following conditions are satisfied.

Item	Condition
Vehicle Doors	Fully open
Temperature Setting	MAX COLD
Blower Speed	HI
A/C Switch	on
R/F Switch	RECIRCULATION
Interior Temperature	25 to 35°C (77 to 95°F)
Engine Speed	2000 rpm

NOTICE:

If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because DTC may be set after the A/C has been operating for a while.

Result	Proceed to
DTC B1423/23 is output	A
DTC B1423/23 is not output	B

B

REPLACE COOLER DRYER

A

16.	REPLACE EXPANSION VALVE

(a) Replace the expansion valve with a new or a known good one (See page ).

HINT:

Replace the expansion valve with a new or a known good one because the expansion valve is either stuck or clogged.

NEXT

17.	CHARGE REFRIGERANT

(a) Add an appropriate amount of refrigerant (See page ).

NEXT

18.	RECHECK DTC

(a) Recheck for the DTC when the following conditions are satisfied.

Item	Condition
Vehicle Doors	Fully open
Temperature Setting	MAX COLD
Blower Speed	HI
A/C Switch	on
R/F Switch	RECIRCULATION
Interior Temperature	25 to 35°C (77 to 95°F)
Engine Speed	2000 rpm

NOTICE:

If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while.

Result	Proceed to
DTC B1423/23 is not output	A
DTC B1423/23 is output	B

A

END

B

REPLACE CONDENSER

19.	REPLACE A/C PRESSURE SENSOR

(a) Replace the A/C pressure sensor (See page ).

HINT:

Since the A/C pressure sensor cannot be inspected while it is removed from the vehicle, replace the A/C pressure sensor with a new or a known good one and check that the condition returns to normal.

NEXT

20.	RECHECK DTC

(a) Recheck for the DTC when the following conditions are satisfied.

Item	Condition
Vehicle Doors	Fully open
Temperature Setting	MAX COLD
Blower Speed	HI
A/C Switch	on
R/F Switch	RECIRCULATION
Interior Temperature	25 to 35°C (77 to 95°F)
Engine Speed	2000 rpm

NOTICE:

If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while.

HINT:

When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from the ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

Result	Proceed to
DTC B1423/23 is not output	A
DTC B1423/23 is output	B

A

END

B

REPLACE A/C AMPLIFIER