Front Power Seat Control System (Diagnostic Codes & Symptom Tests): Overview Lexus CT I

DESCRIPTION

When the position control ECU and switch assembly does not receive a sensor signal despite forward or backward movement of the seat by power seat motor operation, this DTC is stored.

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1. PERFORM ACTIVE TEST USING TECHSTREAM (SLIDE MOTOR) Turn the power switch off. Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Driver Seat / Active Test. Perform the Active Test according to the display on the Techstream. DRIVER SEAT (POSITION CONTROL ECU AND SWITCH ASSEMBLY) Tester Display Test Part Control Range Diagnostic Note Seat Slide Operation Seat sliding operation Front / OFF / Rear - OK Motor operates normally. NG --> See step 5 OK: Go to next step
2. CHECK POSITION CONTROL ECU AND SWITCH ASSEMBLY (SLIDE MOTOR CIRCUIT) Disconnect the X1 slide motor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition X1-2 - X1-3 Sliding switch on 4.8 to 5.1 V NG --> See step 4 OK: Go to next step
3. CHECK SLIDE MOTOR (SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY) Reconnect the X1 slide motor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition X1-2 - Body ground Sliding switch on 4.5 to 4.8 V TEXT IN ILLUSTRATION *a Component with harness connected (Slide Motor (Separate Type Front Seat Cushion Spring Assembly)) NG --> See step 7 OK --> See step 8
4. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY - SLIDE MOTOR) Disconnect the X5 switch connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X5-5 (SSRS) - X1-2 Always Below 1 ohms X5-1 (SGND) - X1-3 Always Below 1 ohms X5-5 (SSRS) - Body ground Always 10 kohms or higher X5-1 (SGND) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 8
5. INSPECT SLIDE MOTOR (SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY) Disconnect the X1 slide motor connector. Check if the seat cushion spring moves smoothly when the auxiliary battery is connected to the slide motor connector terminals. OK Measurement Condition Operational Direction Auxiliary battery positive (+) --> 4 Auxiliary battery negative (-) --> 1 Seat cushion spring moves forward Auxiliary battery positive (+) --> 1 Auxiliary battery negative (-) --> 4 Seat cushion spring moves backward TEXT IN ILLUSTRATION *a Component without harness connected (Slide Motor (Separate Type Front Seat Cushion Spring Assembly)) NG --> See step 7 OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY - SLIDE MOTOR) Disconnect the X4 position control ECU and switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X4-3 (SLD+) - X1-4 Always Below 1 ohms X4-4 (SLD-) - X1-1 Always Below 1 ohms X4-3 (SLD+) - Body ground Always 10 kohms or higher X4-4 (SLD-) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 8
7. REPLACE SLIDE MOTOR (SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY). Refer to «REMOVAL»(ref-568764-S37485810192013072300000)
8. REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY. Refer to «REMOVAL»(ref-568764-S14450742302013072300000)

When the position control ECU and switch assembly does not receive a sensor signal despite forward or backward movement of the seatback by power seat motor operation, this DTC is stored.

Scheme 195

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Scheme 197

1. PERFORM ACTIVE TEST USING TECHSTREAM (RECLINING MOTOR) Turn the power switch off. Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Driver Seat / Active Test. Perform the Active Test according to the display on the Techstream. DRIVER SEAT (POSITION CONTROL ECU AND SWITCH ASSEMBLY) Tester Display Test Part Control Ranger Diagnostic Note Seat Reclining Seat reclining operation Front / OFF / Rear - OK Motor operates normally. NG --> See step 5 OK: Go to next step
2. CHECK POSITION CONTROL ECU AND SWITCH ASSEMBLY (RECLINING MOTOR CIRCUIT) Disconnect the Y1 reclining motor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition Y1-2 - Y1-3 Reclining switch on 4.8 to 5.1 V NG --> See step 4 OK: Go to next step
3. CHECK RECLINING MOTOR (SEPARATE TYPE FRONT SEAT BACK SPRING ASSEMBLY) Reconnect the Y1 reclining motor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition Y1-2 - Body ground Reclining switch on 4.5 to 4.8 V TEXT IN ILLUSTRATION *a Component with harness connected (Reclining Motor (Separate Type Front Seat Back Spring Assembly)) NG --> See step 8 OK --> See step 7
4. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY - RECLINING MOTOR) Disconnect the X5 position control ECU and switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X5-11 (SSRR) - Y1-2 Always Below 1 ohms X5-1 (SGND) - Y1-3 Always Below 1 ohms X5-11 (SSRR) - Body ground Always 10 kohms or higher X5-1 (SGND) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
5. INSPECT RECLINING MOTOR (SEPARATE TYPE FRONT SEAT BACK SPRING ASSEMBLY) Disconnect the Y1 reclining motor connector. Check if the seat back moves smoothly when the auxiliary battery is connected to the reclining motor connector terminals. OK Measurement Condition Operational Direction Auxiliary battery positive (+) --> 4 Auxiliary battery negative (-) --> 1 Seat back moves forward Auxiliary battery positive (+) --> 1 Auxiliary battery negative (-) --> 4 Seat back moves backward TEXT IN ILLUSTRATION *a Component without harness connected (Reclining Motor (Separate Type Front Seat Back Spring Assembly)) NG --> See step 8 OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY - RECLINING MOTOR) Disconnect the X4 position control ECU and switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X4-9 (RCL+) - Y1-4 Always Below 1 ohms X4-11 (RCL-) - Y1-1 Always Below 1 ohms X4-9 (RCL+) - Body ground Always 10 kohms or higher X4-11 (RCL-) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
7. REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY. Refer to «REMOVAL»(ref-568764-S14450742302013072300000)
8. REPLACE RECLINING MOTOR (SEPARATE TYPE FRONT SEAT BACK SPRING ASSEMBLY). Refer to «REMOVAL»(ref-568764-S37485810192013072300000)

When the position control ECU and switch assembly does not receive a sensor signal despite upward or downward movement of the front of the seat cushion by power seat motor operation, this DTC is stored.

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1. PERFORM ACTIVE TEST USING TECHSTREAM (FRONT VERTICAL MOTOR) Turn the power switch off. Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Driver Seat / Active Test. Perform the Active Test according to the display on the Techstream. DRIVER SEAT (POSITION CONTROL ECU AND SWITCH ASSEMBLY) Tester Display Test Part Control Range Diagnostic Note Front Vertical Operation Seat front vertical operation Up / OFF / Down - OK Motor operates normally. NG --> See step 5 OK: Go to next step
2. CHECK POSITION CONTROL ECU AND SWITCH ASSEMBLY (FRONT VERTICAL MOTOR CIRCUIT) Disconnect the X2 front vertical motor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition X2-2 - X2-3 Front vertical switch on 4.8 to 5.1 V NG --> See step 4 OK: Go to next step
3. CHECK FRONT VERTICAL MOTOR (SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY) Reconnect the X2 front vertical motor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition X2-2 - Body ground Front vertical switch on 4.5 to 4.8 V TEXT IN ILLUSTRATION *a Component with harness connected (Front Vertical Motor (Separate Type Front Seat Cushion Spring Assembly)) NG --> See step 8 OK --> See step 7
4. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH - FRONT VERTICAL MOTOR) Disconnect the X5 position control ECU and switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X5-3 (SSFV) - X2-2 Always Below 1 ohms X5-1 (SGND) - X2-3 Always Below 1 ohms X5-3 (SSFV) - Body ground Always 10 kohms or higher X5-1 (SGND) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
5. INSPECT FRONT VERTICAL MOTOR (SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY) Disconnect the X2 front vertical motor connector. Check if the seat cushion spring moves smoothly when the auxiliary battery is connected to the front vertical motor connector terminals. OK Measurement Condition Operational Direction Auxiliary battery positive (+) --> 4 Auxiliary battery negative (-) --> 1 Seat cushion spring moves upward Auxiliary battery positive (+) --> 1 Auxiliary battery negative (-) --> 4 Seat cushion spring moves downward TEXT IN ILLUSTRATION *a Component without harness connected (Front Vertical Motor (Separate Type Front Seat Cushion Spring Assembly)) NG --> See step 8 OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH - FRONT VERTICAL MOTOR) Disconnect the X4 position control ECU and switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X4-8 (FRV+) - X2-4 Always Below 1 ohms X4-5 (FRV-) - X2-1 Always Below 1 ohms X4-8 (FRV+) - Body ground Always 10 kohms or higher X4-5 (FRV-) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
7. REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY. Refer to «REMOVAL»(ref-568764-S14450742302013072300000)
8. REPLACE FRONT VERTICAL MOTOR (SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY). Refer to «REMOVAL»(ref-568764-S37485810192013072300000)

When the position control ECU and switch assembly does not receive a sensor signal despite upward or downward movement of the seat by power seat motor operation, this DTC is stored.

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1. PERFORM ACTIVE TEST USING TECHSTREAM (LIFTER MOTOR) Turn the power switch off. Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Driver Seat / Active Test. Perform the Active Test according to the display on the Techstream. DRIVER SEAT (POSITION CONTROL ECU AND SWITCH ASSEMBLY) Tester Display Test Part Control Range Diagnostic Note Lifter Operation Seat lifter operation Up / OFF / Down - OK Motor operates normally. NG --> See step 5 OK: Go to next step
2. CHECK POSITION CONTROL ECU AND SWITCH ASSEMBLY (LIFTER MOTOR CIRCUIT) Disconnect the X3 lifter motor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition X3-2 - X3-3 Lifter switch on 4.8 to 5.1 V NG --> See step 4 OK: Go to next step
3. CHECK LIFTER MOTOR (SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY) Reconnect the X3 lifter motor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition X3-2 - Body ground Lifter switch on 4.5 to 4.8 V TEXT IN ILLUSTRATION *a Component with harness connected (Lifter Motor (Separate Type Front Seat Cushion Spring Assembly)) NG --> See step 8 OK --> See step 7
4. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY - LIFTER MOTOR) Disconnect the X5 position control ECU and switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X5-4 (SSRL) - X3-2 Always Below 1 ohms X5-1 (SGND) - X3-3 Always Below 1 ohms X5-4 (SSRL) - Body ground Always 10 kohms or higher X5-1 (SGND) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
5. INSPECT LIFTER MOTOR (SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY) Disconnect the X3 lifter motor connector. Check if the seat cushion spring moves smoothly when the auxiliary battery is connected to the lifter motor connector terminals. OK Measurement Condition Operational Direction Auxiliary battery positive (+) --> 4 Auxiliary battery negative (-) --> 1 Seat cushion spring moves upward Auxiliary battery positive (+) --> 1 Auxiliary battery negative (-) --> 4 Seat cushion spring moves downward TEXT IN ILLUSTRATION *a Component without harness connected (Lifter Motor (Separate Type Front Seat Cushion Spring Assembly)) NG --> See step 8 OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY - LIFTER MOTOR) Disconnect the X4 position control ECU and switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X4-10 (LFT+) - X3-4 Always Below 1 ohms X4-12 (LFT-) - X3-1 Always Below 1 ohms X4-10 (LFT+) - Body ground Always 10 kohms or higher X4-12 (LFT-) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
7. REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY. Refer to «REMOVAL»(ref-568764-S14450742302013072300000)
8. REPLACE LIFTER MOTOR (SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY). Refer to «REMOVAL»(ref-568764-S37485810192013072300000)

This DTC is stored when a power seat motor operates (a position control sensor is being supplied with power) and the power supply voltage does not rise to the specified value.

Scheme 202

When a signal is input into the position control ECU and switch assembly, the ECU manages the signals received from the power seat switch, and operates each motor. If the position control ECU and switch assembly receives more than 2 motor operation signals, the motor is stopped. Manual operation is restarted after the position control ECU and switch assembly receives 1 signal only.

Scheme 203

When a signal is input into the position control ECU and switch assembly, the ECU manages the signals received from the front power seat switch, and operates each motor. If the position control ECU and switch assembly receives more than 2 motor operation signals, the motor is stopped. Manual operation is restarted after the position control ECU and switch assembly receives 1 signal only.

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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 position control ECU and switch assembly. After receiving the request signal, the position control ECU and switch assembly memorizes the location data of each motor.

Scheme 206

When any of the M1, M2 or M3 switches is pressed, the outer mirror control ECU assembly (for driver side) sends a switch signal to the main body ECU (multiplex network body ECU) via CAN communication. Then, the main body ECU (multiplex network body ECU) sends a recall request signal to the position control ECU and switch assembly. The position control ECU and switch assembly operates each motor to achieve each memorized position value.

With the power switch off and the driver door closed, pressing the manual lock or unlock switch on the multiplex network master switch assembly while holding a seat memory switch (M1 switch, M2 switch or M3 switch) will register the transmitter recognition code into the seat memory switch that was pressed. After the registration is completed, the answer back buzzer sounds.

Note. The seat position will not be recorded 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.

When a door is unlocked by the wireless unlock function or entry unlock function, the certification ECU (smart key ECU assembly) sends a door unlock signal and key ID signal to the main body ECU (multiplex network body ECU). When the main body ECU (multiplex network body ECU) receives the door unlock signal, it stores the key ID. When the driver door is opened, the memory call and memory command information of the stored key ID is sent to each driving position related control ECU. Each control ECU receives the memory commands and performs the memory call operation according to predetermined control timing values.

See also:
• REMOVAL