Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001A3OB
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): B1497; Communication Malfunction (Bus Ic); 2019 - 2022 MY Avalon HV [04/2018 -        ]

DTC

B1497

Communication Malfunction (Bus Ic)

DESCRIPTION

The air conditioning harness assembly connects the air conditioning amplifier assembly and the servo motors. The air conditioning amplifier assembly supplies power and sends operation instructions to each servo motor through the air conditioning harness assembly. Each servo motor sends damper position information to the air conditioning amplifier assembly.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

B1497

Communication Malfunction (Bus Ic)

Error or open in communication line

  • Air conditioning harness assembly
  • No. 1 air conditioning radiator damper servo sub-assembly
  • No. 2 air conditioning radiator damper servo sub-assembly
  • No. 3 air conditioning radiator damper servo sub-assembly
  • Air conditioning amplifier assembly

Memorized

(10 sec. 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

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Active test.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Air Outlet Servo Pulse (D)

No. 3 air conditioning radiator damper servo sub-assembly pulse

Min.: 128

Max.: 383

Operates between 164 and 278 pulses

Air Outlet Servo Pulse (P)

No. 1 air conditioning radiator damper servo sub-assembly (front passenger side mode) pulse

Min.: 128

Max.: 383

Operates between 234 and 348 pulses

A/O Servo Pulse(Rr D)

No. 2 air conditioning radiator damper servo sub-assembly pulse

Min.: 128

Max.: 383

Operates between 158 and 260 pulses

Body Electrical > Air Conditioner > Active Test

Tester Display

Air Outlet Servo Pulse (D)

Body Electrical > Air Conditioner > Active Test

Tester Display

Air Outlet Servo Pulse (P)

Body Electrical > Air Conditioner > Active Test

Tester Display

A/O Servo Pulse(Rr D)

Result

Proceed to

All of the damper servo motors are malfunctioning

A

One of the damper servo motors is malfunctioning

B

B

GO TO STEP 4

A

2.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Disconnect the No. 1 air conditioning radiator damper servo sub-assembly connector.

(b) Connect the Techstream to the DLC3.

(c) Turn the power switch on (IG).

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / Air Conditioner / Active test.

(f) Perform the Active Test according to the display on the Techstream.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

A/O Servo Pulse(Rr D)

No. 2 air conditioning radiator damper servo sub-assembly pulse

Min.: 128

Max.: 383

Operates between 158 and 260 pulses

Body Electrical > Air Conditioner > Active Test

Tester Display

A/O Servo Pulse(Rr D)

OK:

The damper servo motor operates smoothly.

OK

REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY 2019 MY Avalon HV [04/2018 - 08/2019]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY 2020 - 2022 MY Avalon HV [08/2019 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY

NG

3.

INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY

*a

Component with harness connected

(Air Conditioning Amplifier Assembly)

NOTICE:

When inspecting the air conditioning amplifier assembly, do not bring the tester probes too close to each other as a short circuit may occur.

(a) Disconnect the z9 air conditioning amplifier assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

z9-4 (B BUS) - Body ground

Power switch on (IG)

11 to 14 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

z9-2 (BUS G) - Body ground

Always

Below 1 Ω

(c) Turn the power switch on (IG).

(d) Using an oscilloscope, check the waveform.

Item

Content

Terminal No.

z9-3 (BUS) - z9-2 (BUS G)

Tool Setting

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

Condition

Power switch on (IG)

OK:

Waveform is similar to that shown in the illustration.

HINT:

The waveform varies with the blower speed.

OK

REPLACE AIR CONDITIONING HARNESS ASSEMBLY 2019 MY Avalon HV [04/2018 - 08/2019]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY 2020 - 2022 MY Avalon HV [08/2019 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 2019 - 2020 MY Avalon Avalon HV [04/2018 - 08/2020]; HEATING / AIR CONDITIONING: AIR CONDITIONING AMPLIFIER: REMOVAL 2021 - 2022 MY Avalon Avalon HV [08/2020 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING AMPLIFIER: REMOVAL

4.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Active test.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Air Outlet Servo Pulse (D)

No. 3 air conditioning radiator damper servo sub-assembly pulse

Min.: 128

Max.: 383

Operates between 164 and 278 pulses

Air Outlet Servo Pulse (P)

No. 1 air conditioning radiator damper servo sub-assembly (front passenger side mode) pulse

Min.: 128

Max.: 383

Operates between 234 and 348 pulses

A/O Servo Pulse(Rr D)

No. 2 air conditioning radiator damper servo sub-assembly pulse

Min.: 128

Max.: 383

Operates between 158 and 260 pulses

Body Electrical > Air Conditioner > Active Test

Tester Display

Air Outlet Servo Pulse (D)

Body Electrical > Air Conditioner > Active Test

Tester Display

Air Outlet Servo Pulse (P)

Body Electrical > Air Conditioner > Active Test

Tester Display

A/O Servo Pulse(Rr D)

Result

Proceed to

Only the No. 1 air conditioning radiator damper servo sub-assembly does not operate

A

Only the No. 2 air conditioning radiator damper servo sub-assembly does not operate

B

Only the No. 3 air conditioning radiator damper servo sub-assembly does not operate

Only the No. 3 air conditioning radiator damper servo sub-assembly operates

B

REPLACE AIR CONDITIONING HARNESS ASSEMBLY 2019 MY Avalon HV [04/2018 - 08/2019]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY 2020 - 2022 MY Avalon HV [08/2019 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY

A

5.

INSPECT AIR CONDITIONING HARNESS ASSEMBLY (AIR CONDITIONING AMPLIFIER ASSEMBLY - NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY)

(a) Disconnect the z9 air conditioning amplifier assembly connector.

(b) Disconnect the No. 1 air conditioning radiator damper servo sub-assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

z9-2 (BUS G) - A-3 (GND)

Always

Below 1 Ω

z9-3 (BUS) - A-2 (LIN)

Always

Below 1 Ω

z9-4 (B BUS) - A-1 (+B)

Always

Below 1 Ω

OK

REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY 2019 MY Avalon HV [04/2018 - 08/2019]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY 2020 - 2022 MY Avalon HV [08/2019 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY

NG

REPLACE AIR CONDITIONING HARNESS ASSEMBLY 2019 MY Avalon HV [04/2018 - 08/2019]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY 2020 - 2022 MY Avalon HV [08/2019 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT (for HV Model): DISASSEMBLY