DTC B1440-88: Rear Servo Motor LIN Communication Bus off [11/2023 - ]: 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
   Rear Air Mix Damper Control Servo Motor	This test activates the rear air mix damper control servo motor. (Rear air mix damper servo sub-assembly)	128: Min 384: Max	Operate with the ignition switch ON.
   Rear Air Outlet Damper Control Servo Motor	This test activates the rear air outlet damper control servo motor. (Rear mode damper servo sub-assembly)	128: Min 384: Max	Operate with the ignition switch ON.

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Rear Air Mix Damper Control Servo Motor

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Rear Air Outlet Damper Control Servo Motor

   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 NO. 2 AIR CONDITIONING HARNESS ASSEMBLY. Refer to  DISASSEMBLY [12/2019 - ] 

Result: 

C 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

Result: 

A 

See step  2

Pre-procedure1

1. Disconnect the H64 air conditioning amplifier assembly connector.

   Procedure1

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Component without harness connected (Air Conditioning Amplifier Assembly)

   -

   -

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H64-3 (RBUG) - 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
   H64-2 (RBBU) - H64-3 (RBUG)	Ignition switch off	11 to 14 V

4. Using an oscilloscope, check the waveform.

   Item	Content
   Tester Connection	H64-7 (RBUS) - H64-3 (RBUG)
   Tool Setting	2 V/DIV., 20 μs/DIV.
   Condition	Ignition switch ON

   OK

   The waveform displays properly.

   Result

   Proceed to
   OK
   NG

   Post-procedure1

5. None

Result: 

NG 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

Result: 

OK 

See step  3

Pre-procedure1

1. Connect the H64 air conditioning amplifier assembly connector.
2. Disconnect the M15 No. 2 air conditioning harness assembly connector.

   Procedure1

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to No. 2 Air Conditioning Harness Assembly)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   M15-2 (RBUG) - Body ground	Always	Below 1 Ω

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   M15-4 (RBBU) - M15-2 (RBUG)	Ignition switch off	11 to 14 V

5. Using an oscilloscope, check the waveform.

   Item	Content
   Tester Connection	M15-3 (RBUS) - M15-2 (RBUG)
   Tool Setting	2 V/DIV., 20 μs/DIV.
   Condition	Ignition switch ON

   OK

   The waveform displays properly.

   Result

   Proceed to
   OK
   NG

   Post-procedure1

6. None

Result: 

OK 

REPLACE NO. 2 AIR CONDITIONING HARNESS ASSEMBLY. Refer to  DISASSEMBLY [12/2019 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - NO. 2 AIR CONDITIONING HARNESS ASSEMBLY)