DTC B1497: Communication Malfunction (Bus Ic) [12/2019 - 10/2022]: Procedure

1. Perform the Active Test according to the display on the GTS.

   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 (air mix) pulse	Min.: 128 Max.: 383	Operates between 165 to 257 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 (mode) pulse	Min.: 128 Max.: 383	Operates between 234 to 348 pulses

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Air Mix Servo Targ 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)

   OK

   Damper servo motor is operated.

   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 [12/2019 - 10/2022] 

Result: 

C 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022] 

Result: 

A 

See step  2

1. Disconnect the q1 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
   q1-2 (BUSG) - Body ground	Always	Below 1 Ω

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   q1-4 (BUSB) - q1-2 (BUSG)	Ignition switch off	11 to 14 V

4. Using an oscilloscope, check the waveform.

   Item	Content
   Tester Connection	q1-3 (BUS) - q1-2 (BUSG)
   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 HARNESS ASSEMBLY. Refer to  DISASSEMBLY [12/2019 - 10/2022] 

Result: 

NG 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]