Toyota 4Runner: Communication Malfunction (Bus Ic) (B1497)

Toyota 4Runner Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System(for Manual Air Conditioning System) / Communication Malfunction (Bus Ic) (B1497)

DESCRIPTION

The air conditioning harness assembly connects the No. 1 air conditioning amplifier assembly and each servo motor. The No. 1 air conditioning amplifier assembly supplies power and sends operation instructions to each servo motor through the No. 1 air conditioning amplifier assembly. Each servo motor sends the damper position information to the No. 1 air conditioning amplifier assembly.

DTC Code	DTC Detection Condition	Trouble Area
B1497	An open circuit or malfunction in the communication line.	Air conditioning harness assembly No. 1 air conditioning amplifier assembly

WIRING DIAGRAM

PROCEDURE

1.	CHECK NO. 1 AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Remove the No. 1 air conditioning amplifier assembly with its connectors still connected (See page ).

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z15-2 (BUS G) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
z15-2 (BUS G) - z15-4 (B BUS)	Always	11 to 14 V
z15-2 (BUS G) - z15-3 (BUS)	Ignition switch ON	Pulse generation

Text in Illustration

*a	Component with harness connected (No. 1 Air Conditioning Amplifier Assembly)

Result

Result	Proceed to
OK (When troubleshooting according to problem symptoms table)	A
OK (When troubleshooting according to the DTC)	B
NG	C

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPLACE AIR CONDITIONING HARNESS ASSEMBLY

REPLACE NO. 1 AIR CONDITIONING AMPLIFIER ASSEMBLY

Air Outlet Damper Control Servo Motor Circuit (B1443)

DESCRIPTION The damper servo sub-assembly (mode damper servo) sends pulse signals to inform the No. 1 air conditioning amplifier assembly of the damper position. The No. 1 air conditioning amplif ...

Air Inlet Damper Control Servo Motor Circuit (B1442)

DESCRIPTION The recirculation damper servo sub-assembly sends pulse signals to inform the No. 1 air conditioning amplifier assembly of the damper position. The No. 1 air conditioning amplifier as ...

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