Toyota Venza: BUS IC Communication Malfunction (B1497/97)

Toyota Venza Service Manual / Heating / Air Conditioning / Air Conditioning System / BUS IC Communication Malfunction (B1497/97)

DESCRIPTION

The air conditioning harness connects the A/C amplifier and each servo. The A/C amplifier supplies power and sends operation instructions to each servo through the air conditioning harness. Each servo sends the damper position information to the A/C amplifier.

DTC No.	DTC Detection Condition	Trouble Area
B1497/97	Communication line error or open	Air conditioning harness A/C amplifier

WIRING DIAGRAM

PROCEDURE

1.	INSPECT A/C AMPLIFIER

(a) Remove the A/C amplifier with the connectors still connected.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z7-2 (BUS G) - Body ground	Always	Below 1 Ω

Text in Illustration

*1	Component with harness connected (A/C Amplifier)

REPLACE A/C AMPLIFIER

2.	INSPECT A/C AMPLIFIER

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
z7-4 (B BUS) - z7-2 (BUS G)	Ignition switch off	Below 1 V
z7-4 (B BUS) - z7-2 (BUS G)	Ignition switch ON	11 to 14 V
z7-3 (BUS) - z7-2 (BUS G)	Ignition switch ON	Pulse generation

Text in Illustration

*1	Component with harness connected (A/C Amplifier)

REPLACE AIR CONDITIONING HARNESS

REPLACE A/C AMPLIFIER

Compressor Solenoid Circuit (B1451/51)

DESCRIPTION In this circuit, the A/C compressor receives a refrigerant compression demand signal from the A/C amplifier. Based on this signal, the A/C compressor changes the amount of compressor o ...

Air Mix Damper Control Servo Motor Circuit (Driver Side) (B1446/46)

DESCRIPTION The air mix control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these sign ...

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