DTC B1497: Communication Malfunction (Bus Ic) [08/2020 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Air Conditioner / Active Test.
5. Check the operation by referring to the table below.

   Body Electrical > Air Conditioner > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Air Mix Servo Targ Pulse(D)	No. 1 air conditioning radiator damper servo sub-assembly (driver side air mix) pulse	Min.: 128 Max.: 383	Operates between 165 to 257 pulses
   Air Mix Servo Targ Pulse(P)	No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix) pulse	Min.: 128 Max.: 383	Operates between 255 to 347 pulses
   Air Outlet Servo Pulse (D)	No. 3 air conditioning radiator damper servo sub-assembly (driver side mode) pulse	Min.: 128 Max.: 383	Operates between 164 to 278 pulses
   Air Inlet Damper Targ Pulse	No. 1 blower damper servo sub-assembly pulse	Min.: 128 Max.: 383	Operates between 220 to 256 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 to 348 pulses
   A/O Servo Pulse(Rr D)	No. 2 air conditioning radiator damper servo sub-assembly (rear mode) pulse	Min.: 128 Max.: 383	Operates between 158 to 260 pulses

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Air Mix Servo Targ Pulse(D)

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Air Mix Servo Targ Pulse(P)

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Air Outlet Servo Pulse (D)

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Air Inlet Damper Targ Pulse

   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)

   OK

   Damper servo motor is operated.

6. Check the operation by referring to the table below.

   Result

   Result	Proceed to
   All damper servo motors are not operated	A
   Any damper servo motor is not operated	B
   All damper servo motors are operated	C

Result: 

B 

REPLACE AIR CONDITIONING HARNESS ASSEMBLY 

Refer to DISASSEMBLY [08/2020 - ]

Result: 

C 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 

Refer to REMOVAL [11/2018 - ]

Result: 

A 

See step  2

1. Disconnect the air conditioning amplifier assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component without harness connected (Air Conditioning Amplifier Assembly)

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

   Standard Resistance

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

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   2 (BUS G) - 4 (B BUS)	Ignition switch off	11 to 14 V

4. Using an oscilloscope, check the waveform.

   Item	Content
   Tester Connection	2 (BUS G) - 3 (BUS)
   Tool Setting	2 V/DIV., 20 μs/DIV.
   Condition	Ignition switch ON

   OK

   The waveform displays properly.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 

Refer to REMOVAL [11/2018 - ]

Result: 

NG 

REPLACE AIR CONDITIONING HARNESS ASSEMBLY 

Refer to DISASSEMBLY [08/2020 - ]