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                        | Last Modified: 08-21-2023 | 6.11:8.1.0 | Doc ID: RM100000001B1W2 |  
                        | Model Year Start: 2019 | Model: Avalon | Prod Date Range: [04/2018 - 08/2020] |  
                        | Title: POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for Gasoline Model): C1581; Assist Map Number Un-Writing; 2019 - 2020 MY Avalon [04/2018 - 08/2020] |  
                     
                        
                           | DTC | C1581 | Assist Map Number Un-Writing |  DESCRIPTIONThis DTC will be stored if the power steering ECU (rack and pinion power steering gear assembly) determines that the assist map is not written in the ECU. 
                     
                        
                        
                        
                        
                        
                        
                        
                     
                     
                        
                           | DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Warning Indicate | Return-to-normal Condition | Note |  
                           | C1581 | Assist Map Number Un-Writing | Assist map not written in power steering ECU (rack and pinion power steering gear assembly) | 
                                 
                                    
CAN communication system
ECM
Main body ECU (Multiplex network body ECU)
Skid control ECU (Brake actuator assembly)
AVS ECU (Absorber control ECU) (w/ Adaptive Variable Suspension System)
Rack and pinion power steering gear assembly
 | EPS warning light: Comes on | Assist Map Writing is performed | - |  CAUTION / NOTICE / HINTNOTICE: If the rack and pinion power steering gear assembly has been replaced, perform assist map writing and torque sensor zero point calibration. Click here
                        
                           
                              ![2019 - 2022 MY Avalon [04/2018 -        ]; POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for Gasoline Model): CALIBRATION](/t3Portal/stylegraphics/info.gif)  HINT: Related parts store information necessary for assist map writing. Related Part: 
                     
                        
ECM
Main body ECU (Multiplex network body ECU)
Skid control ECU (Brake actuator assembly)
AVS ECU (Absorber control ECU) (w/ Adaptive Variable Suspension System)
 PROCEDURE
                     
                        
                           | 1.  | PERFORM ASSIST MAP WRITING |  (a) Perform assist map writing. Chassis > EMPS > Utility
                     
                        
                     
                     
                        
                           | Tester Display |  
                           | Signal Check |  (b) Check for DTCs. Chassis > EMPS > Trouble Codes
                     
                        
                           | Result | Proceed to |  
                           | DTC C1581 is output. | A |  
                           | DTC C1581 is not output. | B |  
                     
                        
                           | B |   | END |  
                     
                        | 
                              
                                 | A |  
                                 |   |  |  
                     
                        
                           | 2.  | CHECK CAN COMMUNICATION SYSTEM |  (a) Check for DTCs. Click here
                        
                           
                              ![2019 - 2022 MY Avalon [04/2018 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): HOW TO PROCEED WITH TROUBLESHOOTING](/t3Portal/stylegraphics/info.gif)  
                     
                        
                           | Result | Proceed to |  
                           | CAN communication system DTCs are not output. | A |  
                           | CAN communication system DTCs are output. | B |  
                     
                        | 
                              
                                 | A |  
                                 |   |  |  (a) Confirm if the related part has the correct part number. 
                     
                        
                        
                     
                     
                        
                           | Related Part | ECM |  
                           | Main body ECU (Multiplex network body ECU) |  
                           | Skid control ECU (Brake actuator assembly) |  
                           | AVS ECU (Absorber control ECU) (w/ Adaptive Variable Suspension System) |  NOTICE: When removing the related part to check it, be sure to follow the appropriate procedures and precautions. 
                     
                        
ECM
Click here
                                 
                                    
                                       ![2019 - 2021 MY Avalon [04/2018 - 08/2021]; 2GR-FKS (ENGINE CONTROL): ECM: REMOVAL](/t3Portal/stylegraphics/info.gif) 
Main body ECU (Multiplex network body ECU)
Click here
                                 
                                    
                                       ![2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL](/t3Portal/stylegraphics/info.gif) 
Skid control ECU (Brake actuator assembly)
Click here
                                 
                                    
                                       ![2019 - 2020 MY Avalon [04/2018 - 08/2020]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: BRAKE ACTUATOR (for Gasoline Model): REMOVAL](/t3Portal/stylegraphics/info.gif) 
AVS ECU (Absorber control ECU) (w/ Adaptive Variable Suspension System)
Click here
                                 
                                    
                                       ![2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; SUSPENSION CONTROL: SUSPENSION CONTROL ECU: REMOVAL](/t3Portal/stylegraphics/info.gif)  
                     
                        
                           | Result | Proceed to |  
                           | The related part has the correct part number. | A |  
                           | The related part has an incorrect part number. | B |  
                     
                        | 
                              
                                 | A |  
                                 |   |  |  (a) Select Health Check on the Techstream screen and check if system DTCs of the related part are output. HINT: If system DTCs of the related part are stored, assist map writing to the power steering ECU (rack and pinion power steering gear assembly) may not be performed properly. 
                     
                        
                           | Result | Proceed to |  
                           | System DTCs of the related part are output. | A |  
                           | System DTCs of the related part are not output. | B |  
                     
                        
                           | A |   | REPAIR CIRCUIT INDICATED BY OUTPUT CODE |  
                     
                        
                           | 5.  | REPLACE RELATED PART WITH PART THAT HAS CORRECT PART NUMBER |  (a) Replace the related part with one that has the correct part number. 
                     
                        
ECM
Click here
                                 
                                    
                                       ![2019 - 2021 MY Avalon [04/2018 - 08/2021]; 2GR-FKS (ENGINE CONTROL): ECM: REMOVAL](/t3Portal/stylegraphics/info.gif) 
Main body ECU (Multiplex network body ECU)
Click here
                                 
                                    
                                       ![2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL](/t3Portal/stylegraphics/info.gif) 
Skid control ECU (Brake actuator assembly)
Click here
                                 
                                    
                                       ![2019 - 2020 MY Avalon [04/2018 - 08/2020]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: BRAKE ACTUATOR (for Gasoline Model): REMOVAL](/t3Portal/stylegraphics/info.gif) 
AVS ECU (Absorber control ECU) (w/ Adaptive Variable Suspension System)
Click here
                                 
                                    
                                       ![2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; SUSPENSION CONTROL: SUSPENSION CONTROL ECU: REMOVAL](/t3Portal/stylegraphics/info.gif)  
                     
                        | 
                              
                                 | NEXT |  
                                 |   |  |  (a) Check for DTCs. Chassis > EMPS > Trouble Codes
                     
                        
                           | Result | Proceed to |  
                           | DTCs are not output. | A |  
                           | DTCs are output. | B |  
                     
                        
                           | A |   | END |  |