DTC B14B2: Lost Communication with Front Panel LIN [10/2018 - 07/2022]: Procedure

1. Check for DTCs.

   Body Electrical > Air Conditioner > Trouble Codes 

   Result

   Result	Proceed to
   Only DTC B14B2 is output	A
   DTC B14B2, B14B5 and B14B7 are output	B

Result: 

B 

See step  5

Result: 

A 

See step  2

1. Disconnect the air conditioning control assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Air Conditioning Control Assembly)

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   F28-4 (+B) - Body ground	Power switch off	11 to 14 V
   F28-8 (IG+) - Body ground	Power switch on (IG)	11 to 14 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   F28-1 (E) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Disconnect the F51 air conditioning amplifier assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   F28-6 (LIN1) - F51-14 (LIN1)	Always	Below 1 Ω
   F28-6 (LIN1) or F51-14 (LIN1) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Connect the F51 air conditioning amplifier assembly connector.
2. Turn the power switch on (IG).
3. Using an oscilloscope, check the waveform.

   Item	Content
   Terminal No.	F51-14 (LIN1) - Body ground
   Tool Setting	2 V/DIV., 20 ms./DIV.
   Condition	Power switch on (IG)

   OK

   Waveform is similar to that shown in the illustration.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE AIR CONDITIONING CONTROL ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022] 

Result: 

NG 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022] 

1. Disconnect the F51 air conditioning amplifier assembly connector.
2. Disconnect the F28 air conditioning control assembly connector.
3. Disconnect the F38 refreshing seat switch connector.
4. Disconnect the F21 spiral cable sub-assembly connector.
5. Measure the voltage and resistance according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   F51-14 (LIN1) - F21-3 (LIN)	Always	Below 1 Ω
   F51-14 (LIN1) - F28-3 (LIN1)	Always	Below 1 Ω
   F51-14 (LIN1) - F38-2 (CN2+)	Always	Below 1 Ω
   F51-14 (LIN1), F21-3 (LIN), F28-3 (LIN1) or F38-2 (CN2+) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

1. Clear the DTCs.

   Body Electrical > Air Conditioner > Clear DTCs 

2. Disconnect the F28 air conditioning control assembly connector.
3. Make sure that the DTC detection conditions are met.

   HINT: 

   If the detection conditions are not met, the system cannot detect the malfunction.

4. Check for DTCs.

   Body Electrical > Air Conditioner > Trouble Codes 

   Result

   Result	Proceed to
   Only DTC B14B2 is output	A
   DTC B14B2, B14B5 and B14B7 are output	B

Result: 

A 

REPLACE AIR CONDITIONING CONTROL ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022] 

Result: 

B 

See step  7

1. Clear the DTCs.

   Body Electrical > Air Conditioner > Clear DTCs 

2. Disconnect the F38 refreshing seat switch connector.
3. Make sure that the DTC detection conditions are met.

   HINT: 

   If the detection conditions are not met, the system cannot detect the malfunction.

4. Check for DTCs.

   Body Electrical > Air Conditioner > Trouble Codes 

   Result

   Result	Proceed to
   Only DTC B14B5 is output	A
   DTC B14B2, B14B5 and B14B7 are output	B

Result: 

A 

REPLACE REFRESHING SEAT SWITCH. Refer to  REMOVAL [10/2018 - 07/2022] 

Result: 

B 

See step  8

1. Clear the DTCs.

   Body Electrical > Air Conditioner > Clear DTCs 

2. Disconnect the F21 spiral cable sub-assembly connector.
3. Make sure that the DTC detection conditions are met.

   HINT: 

   If the detection conditions are not met, the system cannot detect the malfunction.

4. Check for DTCs.

   Body Electrical > Air Conditioner > Trouble Codes 

   Result

   Result	Proceed to
   Only DTC B14B7 is output	A
   DTC B14B2, B14B5 and B14B7 are output	B

Result: 

B 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022] 

Result: 

A 

See step  9

1. Remove the spiral cable sub-assembly.

   Refer to REMOVAL [10/2018 - 07/2022]

2. Inspect the spiral cable sub-assembly.

   Refer to INSPECTION [10/2018 - ]

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE HEATED STEERING WHEEL CONTROLLER (STEERING VIBRATION ECU). Refer to  REMOVAL [10/2018 - 07/2022] 

Result: 

NG 

REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022]