Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Power Seat Position is not Memorized

DESCRIPTION

The main body ECU (multiplex network body ECU) receives seat memory switch signals from the outer mirror control ECU assembly LH via CAN communication. If the SET switch is being pressed when one of the M1 or M2 switches is pressed, or if one of the M1 or M2 switches is pressed within 3 seconds of pressing the SET switch, the main body ECU (multiplex network body ECU) sends a memory request signal to the position control ECU assembly. After receiving the request signal, the position control ECU assembly memorizes the location data of each motor.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

• The seat position will not be stored if the SET switch and 2 or more of the seat memory switches (for example, M1 switch and M2 switch) are pressed simultaneously.

  If a memorizing operation has failed, release all of the switches. The seat memory function will not operate unless the switches are released.

• The seat will not return to the memorized position if 2 or more of the seat memory switches (for example, M1 switch and M2 switch) are pressed simultaneously.

  If a restoring operation has failed, release all of the switches. The seat memory restoring function will not operate unless the switches are released.

• The front power seat control system (w/ Memory) uses the CAN communication system. First, confirm that there are no malfunctions in the CAN communication system. Refer to How to Proceed with Troubleshooting.

  Click here

• Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

  Click here

PROCEDURE

(a) Check that each function of the power seat operates normally by using the front power seat switch LH.

Click here

OK:

Each function of the power seat operates normally using the front power seat switch LH.

NG

GO TO PROBLEM SYMPTOMS TABLE

OK

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Mirror L / Data List.

(e) Read the Data List according to the display on the Techstream.

OK:

On the Techstream screen, ON or OFF is displayed accordingly.

NG

GO TO STEP 8

OK

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Driver Seat / Active Test.

(e) Perform the Active Test according to the display on the Techstream.

OK:

Buzzer sounds normally.

NG

REPLACE POSITION CONTROL ECU ASSEMBLY

OK

(a) Replace the outer mirror control ECU assembly LH with a new or known good one.

Click here

NEXT

(a) Check the seat position memory and restoring functions.

Click here

OK:

Seat position memory and restoring functions operate normally.

OK

END (OUTER MIRROR CONTROL ECU ASSEMBLY LH WAS DEFECTIVE)

NG

(a) Replace the position control ECU assembly with a new or known good one.

Click here

NEXT

(a) Check the seat position memory and restoring functions.

Click here

OK:

Seat position memory and restoring functions operate normally.

OK

END (POSITION CONTROL ECU ASSEMBLY WAS DEFECTIVE)

NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

(a) Remove the seat memory switch.

Click here

(b) Inspect the seat memory switch.

Click here

NG

REPLACE SEAT MEMORY SWITCH

OK

(a) Disconnect the I21 outer mirror control ECU assembly LH connector.

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

Standard Resistance:

OK

REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY LH

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR