DESCRIPTION The seat heater
switch (radio and display receiver 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
(radio and display receiver 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 (radio and display receiver assembly) |
- Seat heater switch (radio and display receiver assembly)
- Air conditioning amplifier assembly
- Wire harness or connector
- ECU-IG1 NO. 4 fuse
| WIRING DIAGRAM
 CAUTION / NOTICE / HINT
NOTICE: Inspect the fuses for circuits related to this system before performing the following procedure. PROCEDURE
(a) Clear the DTCs. Click here
 Body Electrical > Air Conditioner > Clear DTCs
|
NEXT |
 | |
(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 (RADIO AND DISPLAY RECEIVER ASSEMBLY) - BODY GROUND) |
| (a) Disconnect the G20 seat heater switch (radio and display receiver assembly) connector. |
 |
|
*a | Front view of wire harness connector
(to Seat Heater Switch (Radio and Display Receiver Assembly)) | | |
(b) Measure the voltage and resistance according to the value(s) in the table below.
Standard Voltage: |
Tester Connection | Condition |
Specified Condition | |
G20-2 (IG+) - Body ground |
Power switch on (IG) |
11 to 14 V | |
G20-2 (IG+) - Body ground |
Power switch off | Below 1 V |
Standard Resistance: |
Tester Connection | Condition |
Specified Condition | |
G20-6 (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 (RADIO AND DISPLAY RECEIVER ASSEMBLY)) |
(a) Disconnect the G35 air conditioning amplifier assembly connector. (b) Measure the resistance according to the value(s) in the table below.
Standard Resistance: |
Tester Connection | Condition |
Specified Condition | |
G35-14 (LIN1) - G20-8 (LIN1) |
Always | Below 1 Ω | |
G35-14 (LIN1) or G20-8(LIN1) - Body ground |
Always | 10 kΩ or higher |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
OK | |
| |
| 5. |
INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY |
| (a) Connect the G35 air conditioning amplifier assembly connector. |
|
(b) Turn the power switch on (IG). (c) Using an oscilloscope, check the waveform.
OK: Waveform is similar to that shown in the illustration. |
Item | Content | |
Terminal No. | G35-14 (LIN1) - Body ground | |
Tool Setting | 2 V/DIV., 20 ms./DIV. | |
Condition | Power switch on (IG) |
| NG |
| REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
|
OK | |
| |
| 6. |
INSPECT SEAT HEATER SWITCH (RADIO AND DISPLAY RECEIVER ASSEMBLY) |
| (a) Connect the G20 seat heater switch (radio and display receiver assembly) connector. |
 |
|
*a | Component with harness connected
(Seat Heater Switch (Radio and Display Receiver Assembly)) | | |
(b) Turn the power switch on (IG). (c) Using an oscilloscope, check the waveform. |
Item | Content | |
Terminal No. | G20-8 (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.
| OK |
| REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
| NG |
| REPLACE SEAT HEATER SWITCH (RADIO AND DISPLAY RECEIVER ASSEMBLY) | | 
