Toyota CH-R Service Manual: Lost Communication with Front Panel LIN (B14B2)

Toyota CH-R Service Manual / Heating / Air Conditioning / Air Conditioning System(for Automatic Air Conditioning System With Top-mounted Air Conditioner Pressure Sensor) / Lost Communication with Front Panel LIN (B14B2)

DESCRIPTION

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

If the LIN communication system malfunctions, the air conditioning amplifier assembly does 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
  • Harness or connector between air conditioning control assembly and power source
  • Harness or connector between air conditioning control assembly and body ground
  • LIN communication system
  • Air conditioning control assembly
  • Air conditioning amplifier assembly

Memorized

(10 seconds 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 - POWER SOURCE)

(a) Disconnect the air conditioning control assembly connector.

*a

Front view of wire harness connector

(to Air Conditioning Control Assembly)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

F61-10 (IG+) - Body ground

Ignition switch ON

11 to 14 V

F61-10 (IG+) - Body ground

Ignition switch off

Below 1 V

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

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

F61-16 (GND) -Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
OK

2.

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

(a) Disconnect the F72 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

F61-2 (LIN1) - F72-3 (LIN1)

Always

Below 1 Ω

F61-2 (LIN1) or F72-3 (LIN1) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Reconnect the F72 air conditioning amplifier assembly connector.

(b) Turn the ignition switch ON.

(c) Connect an oscilloscope to terminals F72-3 (LIN1) and F72-29 (GND) of the air conditioning amplifier assembly and check the waveform.

OK:

Waveform is similar to that shown in the illustration.

Item

Content

Tool Setting

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

Vehicle Condition

Ignition switch ON

*a

Component with harness connected

(Air Conditioning Amplifier Assembly)

-

-
NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

OK

4.

INSPECT AIR CONDITIONING CONTROL ASSEMBLY

(a) Reconnect the F61 air conditioning control assembly connector.

(b) Turn the ignition switch ON.

(c) Connect an oscilloscope to terminals F61-2 (LIN1) and F61-16 (GND) of the air conditioning control assembly and check the waveform.

OK:

Waveform is similar to that shown in the illustration.

Item

Content

Tool Setting

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

Vehicle Condition

Ignition switch ON

*a

Component with harness connected

(Air Conditioning Control Assembly)

-

-
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

NG

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

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