Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001H96A
Model Year Start: 2020 Model: GR Corolla Prod Date Range: [01/2019 - 09/2022]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Manual Air Conditioning System): B14B2; Lost Communication with Front Panel LIN; 2020 - 2022 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2022]

DTC

B14B2

Lost Communication with Front Panel LIN

DESCRIPTION

The air conditioning control assembly communicates with the air conditioning amplifier assembly via LIN communication.

If a malfunction occurs in the LIN communication system, the air conditioning amplifier assembly will not operate, even if the air conditioning control assembly is operated.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

B14B2

Lost Communication with Front Panel LIN

Lost communication with air conditioning control assembly

  • Air conditioning control assembly
  • Harness or connector
  • Air conditioning amplifier assembly

Memorized

(10 sec. 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

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONING CONTROL ASSEMBLY - IG POWER SOURCE AND BODY GROUND)

(a) Disconnect the I37 air conditioning control assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

I37-9 (IG+) - Body ground

Ignition switch ON

11 to 14 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

I37-13 (GND) - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONING CONTROL ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the I49 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

I37-7 (LIN1) - I49-7 (LIN1)

Always

Below 1 Ω

I37-7 (LIN1) or I49-7 (LIN1) - Other terminals and body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Connect the I49 air conditioning amplifier assembly connector.

(b) Turn the ignition switch to ON.

(c) Using an oscilloscope, check the waveform.

OK:

Waveform is similar to that shown in the illustration.

Item

Content

Terminal No.

I49-7 (LIN1) - Body ground

Tool Setting

2 V/DIV., 20 ms./DIV.

Condition

Ignition switch ON

OK

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY