Lexus NX: 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 (for Driver Side) via CAN communication. If the seat memory SET switch is being pressed when one of the M1, M2 or M3 switches is pressed, or if one of the M1, M2 or M3 switches is pressed within 3 seconds of pressing the seat memory SET switch, the main body ECU (multiplex network body ECU) sends a memory request signal to the front power seat switch LH. After receiving the request signal, the front power seat switch LH memorizes the location data of each motor.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
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The front power seat control system (w/ Memory) uses the CAN communication system. First, confirm that there is no malfunction in the CAN communication system. Refer to the How to Proceed with Troubleshooting procedure.
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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 switches. The seat memory function does not operate unless the switches are released.
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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 switches. The seat memory restoring function does not operate unless the switches are released.
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Before replacing the main body ECU (multiplex network body ECU), refer to the Smart Access System with Push-button Start (for Entry Function).
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PROCEDURE
| 1. | CHECK FRONT POWER SEAT OPERATION |
(a) Check that each function of the power seat operates normally by using the front power seat switch LH.
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OK:
Each function of the power seat operates normally using the front power seat switch LH.
| NG | .gif) | GO TO PROBLEM SYMPTOMS TABLE |
|
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| 2. | READ VALUE USING TECHSTREAM (SEAT MEMORY SWITCH1, SEAT MEMORY SWITCH2, SEAT MEMORY SWITCH3, SEAT MEMORY SET SW) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power 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.
Body Electrical > Mirror L > Data List| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| Seat Memory Switch1 | M1 switch | ON or OFF | ON: M1 switch on OFF: M1 switch off | - |
| Seat Memory Switch2 | M2 switch | ON or OFF | ON: M2 switch on OFF: M2 switch off | - |
| Seat Memory Switch3 | M3 switch | ON or OFF | ON: M3 switch on OFF: M3 switch off | - |
| Seat Memory Set SW | SET switch | ON or OFF | ON: SET switch on OFF: SET switch off | - |
| Tester Display |
|---|
| Seat Memory Switch1 |
| Seat Memory Switch2 |
| Seat Memory Switch3 |
| Seat Memory Set SW |
OK:
The Techstream display changes correctly in response to the switch operation.
| NG | | GO TO STEP 6 |
|
| 3. | PERFORM ACTIVE TEST USING TECHSTREAM (BUZZER) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Driver Seat / Active Test.
(e) Read the Data List according to the display on the Techstream.
Body Electrical > Driver Seat > Active Test| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Buzzer | Buzzer operation | OFF/ON | - |
| Tester Display |
|---|
| Buzzer |
OK:
Buzzer sounds/stops normally using the Techstream operation.
| NG | | REPLACE FRONT POWER SEAT SWITCH LH |
|
| 4. | REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY (for Driver Side) |
(a) Replace the outer mirror control ECU assembly (for Driver Side) with a new or known good one.
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|
| 5. | CHECK SEAT POSITION MEMORY AND RESTORING FUNCTION |
(a) Check that the seat position memory and restoring function.
Click here
OK:
Seat position memory and restoring function operate normally.
| OK | | END (OUTER MIRROR CONTROL ECU ASSEMBLY [for Driver Side] WAS DEFECTIVE) |
| NG | | REPLACE FRONT POWER SEAT SWITCH LH |
| 6. | INSPECT SEAT MEMORY SWITCH |
(a) Remove the seat memory switch.
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(b) Inspect the seat memory switch.
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| NG | | REPLACE SEAT MEMORY SWITCH |
|
| 7. | CHECK HARNESS AND CONNECTOR (OUTER MIRROR CONTROL ECU ASSEMBLY [for Driver Side] - SEAT MEMORY SWITCH AND BODY GROUND) |
(a) Disconnect the M5 outer mirror control ECU assembly (for Driver Side) connector.
(b) Disconnect the M12 seat memory switch connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| M5-1 (MM) - M12-1 (MRY) | Always | Below 1 Ω |
| M5-1 (MM) or M12-1 (MRY) - Body ground | Always | 10 kΩ or higher |
| M5-2 (M1) - M12-2 (M1) | Always | Below 1 Ω |
| M5-2 (M1) or M12-2 (M1) - Body ground | Always | 10 kΩ or higher |
| M5-3 (M2) - M12-3 (M2) | Always | Below 1 Ω |
| M5-3 (M2) or M12-3 (M2) - Body ground | Always | 10 kΩ or higher |
| M5-4 (M3) - M12-4 (M3) | Always | Below 1 Ω |
| M5-4 (M3) or M12-4 (M3) - Body ground | Always | 10 kΩ or higher |
| M5-7 (GND) - Body ground | Always | Below 1 Ω |
| M12-5 (E) - Body ground | Always | Below 1 Ω |
| OK | | REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY (for Driver Side) |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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