Toyota Tacoma (2015-2018) Service Manual: Lost Communication with Front Panel LIN (B14B2)

Toyota Tacoma (2015-2018) Service Manual / Air Conditioning / Air Conditioning System(for Automatic Air Conditioning System) / Lost Communication with Front Panel LIN (B14B2)

DESCRIPTION

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

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.	DTC Detection Condition	Trouble Area
B14B3	Lost communication with the air conditioning control assembly.	Harness or connector Air conditioning control assembly Air conditioning amplifier assembly

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING CONTROL ASSEMBLY - POWER SOURCE CIRCUIT)

(a) Disconnect the A33 air conditioning control assembly connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A33-8 (IG+) - Body ground	Ignition switch off	Below 1 V
A33-8 (IG+) - Body ground	Ignition switch ON	11 to 14 V

Standard Resistance:

Tester Connection	Condition	Specified Condition
A33-1 (GND) - Body ground	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Disconnect the A33 air conditioning control assembly connector.

(b) Disconnect the A36 air conditioning amplifier assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A33-2 (STX) - A36-11 (LIN1)	Always	Below 1 Ω
A33-2 (STX) or A36-11 (LIN1) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	REPLACE AIR CONDITIONING CONTROL ASSEMBLY

(a) Replace the air conditioning control assembly (See page HINT: HINT: ).

HINT:

Since the air conditioning control assembly cannot be inspected while it is removed from the vehicle, replace the air conditioning control assembly with a new or known good one and same problem occurs again.

OK:

Same problem does not occurs.

Result	Proceed to
OK	A
NG (When troubleshooting according to Problem Symptoms Table)	B
NG (When troubleshooting according to the DTC)	C

END (AIR CONDITIONING CONTROL ASSEMBLY WAS DEFECTIVE)

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

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