Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Refrigerant Shortage (B14B8)

DESCRIPTION

This DTC is stored if the amount of refrigerant in the air conditioning system is insufficient.

The air conditioning amplifier assembly receives the ambient temperature signal, refrigerant pressure signal, etc. from various sensors.

Based on these signals, the air conditioning amplifier assembly detects the amount of refrigerant.

The A/C switch indicator is turned off and the air conditioning system is stopped if the amount of refrigerant is insufficient.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Memory
B14B8	Refrigerant Shortage	When following condition is detected in refrigerant shortage check in normal operation: Amount of refrigerant is insufficient	Refrigerant pipe line Cooler expansion valve Air conditioning amplifier assembly	Memorized (15 min. or more)*

CAUTION / NOTICE / HINT

HINT:

If DTC B1423/23 and B14B8 are output at the same time, troubleshoot for DTC B1423/23 first.

Click here

PROCEDURE

1.	CHECK FOR AIR CONDITIONING SYSTEM LEAK

(a) Install a manifold gauge set.

(b) Recover the refrigerant from the air conditioning system using a refrigerant recovery unit.

(c) Evacuate the air conditioning system and check that vacuum can be maintained in it.

OK:

Vacuum can be maintained in the air conditioning system.

HINT:

If vacuum cannot be maintained in the air conditioning system, refrigerant may be leaking from it. In this case, it is necessary to repair or replace the leaking part of the air conditioning system.

NG

GO TO STEP 7

OK

2.	CHARGE SYSTEM WITH REFRIGERANT

(a) Add an appropriate amount of refrigerant.

Click here

NEXT

3.	CHECK FOR DTC

(a) Check for DTCs when the following conditions are met.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Measurement Condition:

Item	Condition
A/C switch	On
A/C operation time	15 minutes or more
Ambient temperature*	0 to 49°C (32 to 120°F)
Engine coolant temperature	45°C (113°F) or more
Engine condition	Engine running

Result	Proceed to
DTC B14B8 is output	A
DTC B14B8 is not output	B

B

END

A

4.	REPLACE COOLER EXPANSION VALVE

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

Click here

HINT:

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

NEXT

5.	CHARGE SYSTEM WITH REFRIGERANT

(a) Add an appropriate amount of refrigerant.

Click here

NEXT

6.	CHECK FOR DTC

(a) Check for DTCs when the following conditions are met.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Measurement Condition:

Item	Condition
A/C switch	On
A/C operation time	15 minutes or more
Ambient temperature*	0 to 49°C (32 to 120°F)
Engine coolant temperature	45°C (113°F) or more
Engine condition	Engine running

Result	Proceed to
DTC B14B8 is output	A
DTC B14B8 is not output	B

A

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

B

END

7.	REPAIR AIR CONDITIONING SYSTEM LEAK

(a) Identify the area where refrigerant leaks.

Click here

(b) Repair the identified area of the air conditioning system.

(c) Evacuate the air conditioning system.

NEXT

8.	CHARGE SYSTEM WITH REFRIGERANT

(a) Add an appropriate amount of refrigerant.

Click here

NEXT

9.	CHECK FOR DTC

(a) Check for DTCs when the following conditions are met.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Measurement Condition:

Item	Condition
A/C switch	On
A/C operation time	15 minutes or more
Ambient temperature*	0 to 49°C (32 to 120°F)
Engine coolant temperature	45°C (113°F) or more
Engine condition	Engine running

Result	Proceed to
DTC B14B8 is output	A
DTC B14B8 is not output	B

B

END

A

10.	REPLACE COOLER EXPANSION VALVE

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

Click here

HINT:

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

NEXT

11.	CHARGE SYSTEM WITH REFRIGERANT

(a) Add an appropriate amount of refrigerant.

Click here

NEXT

12.	CHECK FOR DTC

(a) Check for DTCs when the following conditions are met.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Measurement Condition:

Item	Condition
A/C switch	On
A/C operation time	15 minutes or more
Ambient temperature*	0 to 49°C (32 to 120°F)
Engine coolant temperature	45°C (113°F) or more
Engine condition	Engine running

Result	Proceed to
DTC B14B8 is output	A
DTC B14B8 is not output	B

A

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

B

END