Lexus NX: 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 air conditioning system is stopped if the amount of refrigerant is insufficient in the cycle.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Memory	Note
B14B8	Refrigerant Shortage	When the following condition is detected using the refrigerant gas volume check in normal operation: The amount of refrigerant is insufficient.	Refrigerant pipe line Cooler expansion valve Air conditioning amplifier assembly	Memorized (15 minutes or more)	-

HINT:

The air conditioning amplifier assembly stores the DTC of the respective malfunction if it has occurred for the period of time indicated in the brackets.

CAUTION / NOTICE / HINT

NOTICE:

When the auxiliary battery is disconnected or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization.

Click here

HINT:

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

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) Clear the DTC.

Click here

Body Electrical > Air Conditioner > Clear DTCs

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

Click here

Body Electrical > Air Conditioner > Trouble Codes Measurement Condition

Item	Condition
*: If the ambient temperature is not within the range shown, do not perform this check.
A/C Switch	On
Blower speed	Lo or more
Air conditioning operation time	15 minutes or more
Ambient temperature*	0 to 49°C (32 to 120°F)
Engine coolant temperature	45°C (113°F) or higher

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

A

END

B

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) Clear the DTC.

Click here

Body Electrical > Air Conditioner > Clear DTCs

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

Click here

Body Electrical > Air Conditioner > Trouble Codes Measurement Condition

Item	Condition
*: If the ambient temperature is not within the range shown, do not perform this check.
A/C Switch	On
Blower speed	Lo or more
Air conditioning operation time	15 minutes or more
Ambient temperature*	0 to 49°C (32 to 120°F)
Engine coolant temperature	45°C (113°F) or higher

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

A

END (COOLER EXPANSION VALVE IS DEFECTIVE)

B

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

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) Clear the DTC.

Click here

Body Electrical > Air Conditioner > Clear DTCs

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

Click here

Body Electrical > Air Conditioner > Trouble Codes Measurement Condition

Item	Condition
*: If the ambient temperature is not within the range shown, do not perform this check.
A/C Switch	On
Blower speed	Lo or more
Air conditioning operation time	15 minutes or more
Ambient temperature*	0 to 49°C (32 to 120°F)
Engine coolant temperature	45°C (113°F) or higher

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

A

END (COOLER EXPANSION VALVE IS DEFECTIVE)

B

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) Clear the DTC.

Click here

Body Electrical > Air Conditioner > Clear DTCs

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

Click here

Body Electrical > Air Conditioner > Trouble Codes Measurement Condition

Item	Condition
*: If the ambient temperature is not within the range shown, do not perform this check.
A/C Switch	On
Blower speed	Lo or more
Air conditioning operation time	15 minutes or more
Ambient temperature*	0 to 49°C (32 to 120°F)
Engine coolant temperature	45°C (113°F) or higher

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

A

END (COOLER EXPANSION VALVE IS DEFECTIVE)

B

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

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