DTC B14B5: Lost Communication with Front Seat Temperature Adjustment Switch LIN [02/2017 - 05/2018]: Procedure

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [02/2017 - ]

   Body Electrical > Air Conditioner > Clear DTCs 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  2

1. Check for DTCs.

   Refer to DTC CHECK / CLEAR [02/2017 - ]

   Body Electrical > Air Conditioner > Trouble Codes 

   OK

   DTC B14B5 is not output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [02/2017 - 10/2017]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2017 - 05/2018] 

Result: 

NG 

See step  3

1. Disconnect the seat heater switch (air conditioning control assembly) connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   F61-10 (IG+) - Body ground	Ignition switch ON	11 to 14 V
   	Ignition switch off	Below 1 V

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   F61-16 (GND) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Disconnect the F61 seat heater switch (air conditioning control assembly) connector.
2. Disconnect the F72 air conditioning amplifier assembly connector.
3. Measure the resistance according to the value(s) in the chart below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   F61-2 (LIN1) - F72-3 (LIN1)	Always	Below 1 Ω
   F61-2 (LIN1) or F72-3 (LIN1) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Temporarily replace the seat heater switch (air conditioning control assembly) with a new or known good one.

   Refer to REMOVAL [02/2017 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  6

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [02/2017 - ]

   Body Electrical > Air Conditioner > Clear DTCs 

   OK

   DTC B14B5 is not output.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  7

1. Check for DTCs.

   Refer to DTC CHECK / CLEAR [02/2017 - ]

   Body Electrical > Air Conditioner > Trouble Codes 

   OK

   DTC B14B5 is not output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END (SEAT HEATER SWITCH (AIR CONDITIONING CONTROL ASSEMBLY) WAS DEFECTIVE) 

Result: 

NG 

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [02/2017 - 05/2018]