Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM1000000025R2E
Model Year Start: 2023 Model: GR Corolla Prod Date Range: [09/2022 - 11/2022]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (except TMC Made, and Gasoline Model, with Automatic Air Conditioning System): B14B8; Refrigerant Shortage; 2023 MY Corolla Corolla Hatchback GR Corolla [09/2022 - 11/2022]

DTC

B14B8

Refrigerant Shortage

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.

If the amount of refrigerant is insufficient, the A/C switch indicator will turn off and the air conditioning system will stop operating.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

B14B8

Refrigerant Shortage

The following condition is detected in the normal operation refrigerant shortage check:

Amount of refrigerant is insufficient
  • Refrigerant line
  • Cooler expansion valve
  • Air conditioner pressure sensor
  • Harness or connector
  • Air conditioning amplifier assembly

Memorized

(10 min. or more)*
  • *: The air conditioning amplifier assembly stores this DTC if the malfunction has occurred for the period of time indicated in the brackets.

WIRING DIAGRAM

PROCEDURE

1.

CHECK REFRIGERANT PRESSURE

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Regulator Pressure Sensor

Air conditioner pressure sensor

Min.: -456.68 kPaG

Max.: 3294.37 kPaG

Actual refrigerant pressure displayed
  • Refrigerant line (gas leak etc.)
  • Air conditioner pressure sensor circuit malfunction

Body Electrical > Air Conditioner > Data List

Tester Display

Regulator Pressure Sensor

(f) Install a manifold gauge set.

Click here 2020 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 -        ]; HEATING / AIR CONDITIONING: REFRIGERANT (for HFO-1234yf(R1234yf)): ON-VEHICLE INSPECTION

(g) Read the manifold gauge set with the following conditions met.

Measurement Condition:

Item

Condition

Vehicle doors

Fully open

Temperature setting

MAX COLD

Blower speed

HI

A/C switch

On

Recirculation/fresh switch

RECIRCULATION

Interior temperature

30 to 35°C (86 to 95°F)

Standard Pressure:

Low pressure side

150 to 250 kPa (1.5 to 2.5 kgf/cm2, 22 to 36 psi)

High pressure side

1370 to 1570 kPa (14 to 16 kgf/cm2, 199 to 228 psi)

(h) Compare the values displayed in the Data List and on the manifold gauge set.

OK:

The values displayed in the Data List and on the manifold gauge set match.

OK

INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET

NG

2.

CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

(a) Disconnect the A61 air conditioner pressure sensor connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A61-3 (+) - Body ground

Engine switch on (IG)

0.62 to 4.73 V*

*: While sensor voltage is 5 V.

NG

GO TO STEP 7

OK

3.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONER PRESSURE SENSOR - BODY GROUND)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A61-1 (-) - Body ground

Always

Below 1 Ω
NG

GO TO STEP 6

OK

4.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONER PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the I48 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A61-2 (PR) - I48-6 (PRE)

Always

Below 1 Ω

A61-2 (PR) or I48-6 (PRE) - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

INSPECT AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)

*a

Component with harness connected

(Air Conditioning Amplifier Assembly)

(a) Measure the voltage with the following conditions met.

Measurement Condition:

Item

Condition

Vehicle doors

Fully open

Temperature setting

MAX COLD

Blower speed

HI

A/C switch

On

Recirculation/fresh switch

RECIRCULATION

Interior temperature

25 to 35°C (77 to 95°F)

NOTICE:

  • If refrigerant pressure on the high pressure side becomes extremely high during the inspection (if the voltage exceeds 4.61 V), a fail-safe function will stop compressor operation. In this case, make sure to measure the voltage before the fail-safe function operates.
  • It is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the malfunction may recur after a while.

HINT:

When the ambient air temperature is low(below -1.5°C (29.3°F)), the compressor with pulley will be stopped, due to inputs of the thermistor assembly and No. 1 cooler thermistor, 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

I48-6 (PRE) - Body ground

Engine switch on (IG)

(A/C switch: On)

0.74 to 4.61 V

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG).

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(f) Read the Data List according to the display on the Techstream.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Regulator Pressure Sensor

Air conditioner pressure sensor

Min.: -456.68 kPaG

Max.: 3294.37 kPaG

Actual refrigerant pressure displayed
  • Refrigerant line (gas leak etc.)
  • Air conditioner pressure sensor circuit malfunction

Body Electrical > Air Conditioner > Data List

Tester Display

Regulator Pressure Sensor

OK:

The voltage and value displayed in the Data List change.

Result

Proceed to

OK

A

NG (The voltage changes but the value displayed in the Data List does not change.)

NG (The voltage does not change.)

B
A

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

B

REPLACE AIR CONDITIONER PRESSURE SENSOR

6.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONER PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the I48 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A61-1 (-) - I48-15 (SG-4)

Always

Below 1 Ω

A61-1 (-) or I48-15 (SG-4) - Other terminals and body ground

Always

10 kΩ or higher
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

7.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONER PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the I48 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A61-3 (+) - I48-11 (S5-3)

Always

Below 1 Ω

A61-3 (+) or I48-11 (S5-3) - Other terminals and body ground

Always

10 kΩ or higher
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR