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 ...

Other materials about Toyota 4Runner:

Brake Warning Light does not Come ON
DESCRIPTION Refer to Brake Warning Light Remains ON (See page ). WIRING DIAGRAM Refer to Brake Warning Light Remains ON (See page ). CAUTION / NOTICE / HINT NOTICE: When replacing the master cylinder solenoid, perform calibration (See page ). PROC ...

Front Passenger Side Solar Sensor Short Circuit (B14A3)
DESCRIPTION The automatic light control sensor (solar sensor), which is installed on the upper side of the instrument panel, detects sunlight and controls the air conditioning in auto mode. The output current from the solar sensor varies according to th ...