Toyota CH-R Service Manual: Lost Communication with Front Seat Temperature Adjustment Switch LIN (B14B5)

Toyota CH-R Service Manual / Seat / Seat Heater System / Lost Communication with Front Seat Temperature Adjustment Switch LIN (B14B5)

DESCRIPTION

The seat heater switch (air conditioning control assembly) communicates with the air conditioning amplifier assembly via LIN communication.

If the LIN communication system is malfunctioning, the air conditioning amplifier assembly will not operate even if the seat heater switch (air conditioning control assembly) is operated.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B14B5

Lost Communication with Front Seat Temperature Adjustment Switch LIN

Lost communication with the seat heater switch (air conditioning control assembly)
  • Seat heater switch (air conditioning control assembly)
  • Air conditioning amplifier assembly
  • Wire harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • When DTC B14B2 and B14B5 are output simultaneously, first perform troubleshooting for the air conditioning system.
    • for TMMT Made:

      Click here

    • for TMC Made:

      Click here

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Click here

Body Electrical > Air Conditioner > Clear DTCs
NEXT

2.

CHECK FOR DTC

(a) Check for DTCs.

Click here

Body Electrical > Air Conditioner > Trouble Codes

OK:

DTC B14B5 is not output.

OK

USE SIMULATION METHOD TO CHECK

NG

3.

CHECK HARNESS AND CONNECTOR (IG POWER SUPPLY - SEAT HEATER SWITCH (AIR CONDITIONING CONTROL ASSEMBLY) - BODY GROUND)

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

*a

Front view of wire harness connector

(to Seat Heater Switch (Air Conditioning Control Assembly))

(b) Measure the voltage and resistance according to the value(s) in the table 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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F61-16 (GND) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - SEAT HEATER SWITCH (AIR CONDITIONING CONTROL ASSEMBLY))

(a) Disconnect the F61 seat heater switch (air conditioning control assembly) connector.

(b) Disconnect the F72*1 or F139*2 air conditioning amplifier assembly connector.

  • *1: for TMMT Made
  • *2: for TMC Made

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

Standard Resistance:

for TMMT Made

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
for TMC Made

Tester Connection

Condition

Specified Condition

F61-2 (LIN1) - F139-14 (LIN1)

Always

Below 1 Ω

F61-2 (LIN1) or F139-14 (LIN1) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

REPLACE SEAT HEATER SWITCH (AIR CONDITIONING CONTROL ASSEMBLY)

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

Click here

NEXT

6.

CLEAR DTC

(a) Clear the DTCs.

Click here

Body Electrical > Air Conditioner > Clear DTCs

OK:

DTC B14B5 is not output.

NEXT

7.

CHECK FOR DTC

(a) Check for DTCs.

Click here

Body Electrical > Air Conditioner > Trouble Codes

OK:

DTC B14B5 is not output.

OK

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

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

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