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                        | Last Modified: 08-21-2023 | 6.11:8.1.0 | Doc ID: RM100000001A3OK |  
                        | Model Year Start: 2019 | Model: Avalon HV | Prod Date Range: [04/2018 -                    
                                       ] |  
                        | Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): B14B2; Lost Communication with Front Panel LIN; 2019 - 2022 MY Avalon HV [04/2018 -        ] |  
                     
                        
                           | DTC | B14B2 | Lost Communication with Front Panel LIN |  DESCRIPTIONThe air conditioning control panel (radio and display receiver assembly) communicates with the air conditioning amplifier assembly via LIN communication. If a malfunction occurs in the LIN communication system, the air conditioning amplifier assembly will not operate, even if the air conditioning control panel (radio and display receiver assembly) is operated. 
                     
                        
                        
                        
                        
                        
                     
                     
                        
                           | DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Memory |  
                           | B14B2 | Lost Communication with Front Panel LIN | Lost communication with air conditioning control panel (radio and display receiver assembly) | 
                                 
                                    
Harness or connector
Air conditioning control panel (radio and display receiver assembly)
Air conditioning amplifier assembly
 | Memorized (10 sec. or more)* |  
                     
                        
*: The air conditioning amplifier assembly stores this DTC if the malfunction has occurred for the period of time indicated in the brackets.
 WIRING DIAGRAM  CAUTION / NOTICE / HINTNOTICE: Inspect the fuses for circuits related to this system before performing the following procedure. PROCEDURE
                     
                        
                           | 1.  | CHECK HARNESS AND CONNECTOR (AIR CONDITIONING CONTROL PANEL (RADIO AND DISPLAY RECEIVER ASSEMBLY) - POWER SOURCE AND BODY GROUND) |  (a) Disconnect the G20 air conditioning control panel (radio and display receiver assembly) connector. (b) Measure the voltage and resistance according to the value(s) in the table below. Standard Voltage:  
                     
                        
                        
                        
                     
                     
                        
                           | Tester Connection | Condition | Specified Condition |  
                           | G20-3 (+B) - Body ground | Power switch off | 11 to 14 V |  
                           | G20-2 (IG+) - Body ground | Power switch on (IG) | 11 to 14 V |  
                           | G20-10 (ACC) - Body ground | Power switch on (ACC) | 11 to 14 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 |  
                                 |   |  |  
                     
                        
                           | 2.  | CHECK HARNESS AND CONNECTOR (AIR CONDITIONING CONTROL PANEL (RADIO AND DISPLAY RECEIVER ASSEMBLY) - AIR CONDITIONING AMPLIFIER 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 |  
                           | G20-8 (LIN1) - G35-14 (LIN1) | Always | Below 1 Ω |  
                           | G20-8 (LIN1) or G35-14 (LIN1) - Other terminals and body ground | Always | 10 kΩ or higher |  
                     
                        
                           | NG |   | REPAIR OR REPLACE HARNESS OR CONNECTOR |  
                     
                        | 
                              
                                 | OK |  
                                 |   |  |  
                     
                        
                           | 3.  | 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. 
                     
                        
                        
                     
                     
                        
                           | Item | Content |  
                           | Terminal No. | G35-14 (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. 
                     
                        | 
                              
                                 | OK |  
                                 |   |  |  
                     
                        
                           | 4.  | INSPECT AIR CONDITIONING CONTROL PANEL (RADIO AND DISPLAY RECEIVER ASSEMBLY) |    
                     
                        
                        
                     
                     
                        
                           | *a | Component with harness connected (Air Conditioning Control Panel (Radio and Display Receiver Assembly)) |  (a) Connect the G20 air conditioning control panel (radio and display receiver assembly) connector. (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. |