Power Seat Control System (Diagnostics): Overview Lexus LX J200

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COMMUNICATION TABLE

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SYSTEM DESCRIPTION

1. FRONT POWER SEAT CONTROL SYSTEM DESCRIPTION The driver seat is equipped with slide, reclining, lifter, front vertical, variable and lumbar support adjustment functions. The passenger seat is equipped with slide, reclining, lifter, front vertical and lumbar support adjustment functions. The memory call function uses the key ID code of the key to memorize and reproduce the appropriate driving position for each individual who possesses a master key or sub key.
2. FUNCTION OF MAIN COMPONENT The following functions are available. Component Function Seat slide motor Receives signal from front power seat switch, and slides seat forward and rearward. Seat reclining motor Receives signal from front power seat switch, and tilts and reclines seat. Seat front vertical motor Receives signal from front power seat switch, and raises and lowers front of seat cushion. Seat lifter motor Receives signal from front power seat switch, and raises and lowers seat cushion. Seat variable cushion motor Receives signal from seat variable cushion switch and varies length of driver side seat cushion. Lumbar support adjuster motor Activated based on signal from lumbar support switch. Adjusts lumbar support. Seat control switch Based on switches operated, seat adjuster signals are input into position control ECU and seat is adjusted accordingly. Seat memory switch When seat memory SET switch and seat memory switch are pressed simultaneously, signal is input to outer mirror control ECU and seat position is recorded. Then, when seat memory switch is pressed, signal is input to outer mirror control ECU and seat position changes according to memory.
3. SYSTEM OPERATION The front power seat functions which can be adjusted with power seat motors and/or memorized are shown in the chart below. Seat Adjustment Function Driver Seat Passenger Seat Fore-and-Aft Slide Power and memory Power Reclining Power and memory Power Front Vertical Height Power and memory Power Lifter Power and memory Power Variable Power - Lumbar support Power Power For the driver side memory function, the seat memory switch operation is first transferred from the outer mirror control ECU to the position control ECU and switch via the CAN communication line. Then, either the seat position is stored in memory or a previously stored seat position is recalled.

DESCRIPTION

When a signal is input into the position control ECU, the ECU manages the signals received from the front power seat switch LH, and operates each motor. When 2 or more signals are input, the motors only operate when the signals are from the slide switch and reclining switch.

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1. INSPECT FUSE (FR P/SEAT LH, ECU-B2) Remove the FR P/SEAT LH fuse from the main body ECU. Remove the ECU-B2 fuse from the engine room relay block. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition FR P/SEAT LH fuse Always Below 1 ohms ECU-B2 fuse Always Below 1 ohms NG --> REPLACE FUSE OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH - BATTERY AND BODY GROUND) Disconnect the c14 and c15 switch connectors. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition c14-5 (+B) - Body ground Always 11 to 14 V c15-8 (SYSB) - Body ground Always 11 to 14 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition c14-1 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 3
3. REPLACE POSITION CONTROL ECU AND SWITCH. Refer to «REMOVAL»(ref-385219-S06542436282011021400000)

When the front power seat switch is operated, a command signal is sent to the position control ECU. The position control ECU then controls the appropriate seat motor as needed. The position control ECU is designed so that a malfunction of the seat memory system will not interfere with manual seat control.

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1. CHECK FRONT POWER SEAT OPERATION Check that each function of the power seat operates normally by using the front power seat switches. RESULT Result Proceed to All front power seat switch operations are malfunctioning except lumbar support switch and seat variable cushion switch operation A Only lumbar support switch operation is malfunctioning B Only seat variable cushion switch operation is malfunctioning C C --> See step 13 B --> See step 6 A: Go to next step
2. READ VALUE USING TECHSTREAM (FRONT POWER SEAT SWITCH) Using the Techstream, read the Data List. DRIVER SEAT Tester Display Measurement Item/Range Normal Condition Diagnostic Note Reclining Rear Reclining switch signal (Rearward) / ON or OFF ON: Reclining switch (Rearward) on OFF: Reclining switch (Rearward) off - Reclining Front Reclining switch signal (Forward) / ON or OFF ON: Reclining switch (Forward) on OFF: Reclining switch (Forward) off - Front Vertical Down Front vertical switch signal (Downward) / ON or OFF ON: Front vertical switch (Downward) on OFF: Front vertical switch (Downward) off - Front Vertical Up Front vertical switch signal (Upward) / ON or OFF ON: Front vertical switch (Upward) on OFF: Front vertical switch (Upward) off - Lifter Switch Down Lifter switch signal (Downward) / ON or OFF ON: Lifter switch (Downward) on OFF: Lifter switch (Downward) off - Lifter Switch Up Lifter switch signal (Upward) / ON or OFF ON: Lifter switch (Upward) on OFF: Lifter switch (Upward) off - Slide Rear Sliding switch signal (Rearward) / ON or OFF ON: Sliding switch (Rearward) on OFF: Sliding switch (Rearward) off - Slide Front Sliding switch signal (Forward) / ON or OFF ON: Sliding switch (Forward) on OFF: Sliding switch (Forward) off - OK On the Techstream screen, each item changes between ON and OFF according to above chart. NG --> See step 9 OK: Go to next step
3. PERFORM ACTIVE TEST USING TECHSTREAM (FRONT POWER SEAT MOTOR) Using the Techstream, perform the Active Test. DRIVER SEAT Tester Display Test Part Control Range Diagnostic Note Seat Reclining Seat reclining operation Front / OFF / Rear - Front Vertical Operation Seat front vertical operation Up / OFF / Down - Lifter Operation Seat lifter operation Up / OFF / Down - Seat Slide Operation Seat sliding operation Front / OFF / Rear - OK The power seat motors operate normally. NG --> See step 4 OK --> See step 9
4. INSPECT FRONT SEAT ASSEMBLY LH (FRONT POWER SEAT MOTOR) Remove the front seat assembly LH. Refer to «REMOVAL»(ref-385219-S15042633902011021400000) . Check operation of the slide motor. Check if the seat moves smoothly when the battery is connected to the slide motor connector terminals. OK Measurement Condition Specified Condition Battery positive (+) --> 1 Battery negative (-) --> 2 Forward Battery positive (+) --> 2 Battery negative (-) --> 1 Rearward Check operation of the front vertical motor. Check if the seat moves smoothly when the battery is connected to the front vertical motor connector terminals. OK Measurement Condition Specified Condition Battery positive (+) --> 1 Battery negative (-) --> 2 Upward Battery positive (+) --> 2 Battery negative (-) --> 1 Downward Check operation of the lifter motor. Check if the seat moves smoothly when the battery is connected to the lifter motor connector terminals. OK Measurement Condition Specified Condition Battery positive (+) --> 2 Battery negative (-) --> 1 Upward Battery positive (+) --> 1 Battery negative (-) --> 2 Downward Check operation of the reclining motor. Check if the seat moves smoothly when the battery is connected to the reclining motor connector terminals. OK Measurement Condition Specified Condition Battery positive (+) --> 2 Battery negative (-) --> 1 Forward Battery positive (+) --> 1 Battery negative (-) --> 2 Rearward NG --> See step 10 OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH - POWER SEAT MOTOR) Disconnect the c14 switch connector. Disconnect the c17, c18, c19 and c20 motor connectors. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition c14-3 (SLD-) - c17-2 Always Below 1 ohms c14-2 (SLD+) - c17-1 Always Below 1 ohms c14-4 (FRV-) - c19-2 Always Below 1 ohms c14-6 (FRV+) - c19-1 Always Below 1 ohms c14-9 (LFT-) - c18-1 Always Below 1 ohms c14-7 (LFT+) - c18-2 Always Below 1 ohms c14-10 (RCL-) - c20-1 Always Below 1 ohms c14-8 (RCL+) - c20-2 Always Below 1 ohms c14-1 (GND) - Body ground Always Below 1 ohms c14-3 (SLD-) or c17-2 - Body ground Always 10 kohms or higher c14-2 (SLD+) or c17-1 - Body ground Always 10 kohms or higher c14-4 (FRV-) or c19-2 - Body ground Always 10 kohms or higher c14-6 (FRV+) or c19-1 - Body ground Always 10 kohms or higher c14-9 (LFT-) or c18-1 - Body ground Always 10 kohms or higher c14-7 (LFT+) or c18-2 - Body ground Always 10 kohms or higher c14-10 (RCL-) or c20-1 - Body ground Always 10 kohms or higher c14-8 (RCL+) or c20-2 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 9
6. INSPECT LUMBAR SUPPORT SWITCH Remove the lumbar support switch. Refer to «REMOVAL»(ref-385219-S23154430862011021400000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 3 (B) - 4 (H) Hold Below 1 ohms 1 (R) - 2 (E2) 4 (H) - 5 (E2) Off 1 (R) - 2 (E2) 4 (H) - 5 (E2) Release 1 (R) - 3 (B) NG --> See step 11 OK: Go to next step
7. INSPECT LUMBAR SUPPORT ADJUSTER ASSEMBLY Remove the lumbar support adjuster. Refer to «REMOVAL»(ref-385219-S41550277062011021400000) . Check operation of the lumbar support adjuster. Check that the lumbar support adjuster moves smoothly when the battery is connected to the lumbar support adjuster motor connector terminals. OK Measurement Condition Specified Condition Battery positive (+) --> 1 Battery negative (-) --> 2 Clockwise Battery positive (+) --> 2 Battery negative (-) --> 1 Counterclockwise NG --> See step 12 OK: Go to next step
8. CHECK HARNESS AND CONNECTOR (LUMBAR SUPPORT SWITCH - BATTERY AND BODY GROUND) Disconnect the c16 switch connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition c16-3 (B) - Body ground Always 11 to 14 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition c16-5 (E2) - Body ground Always Below 1 ohms c16-2 (E2) - Body ground NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPAIR OR REPLACE HARNESS OR CONNECTOR (LUMBAR SUPPORT SWITCH - LUMBAR SUPPORT ADJUSTER ASSEMBLY)
9. REPLACE POSITION CONTROL ECU AND SWITCH. Refer to «REMOVAL»(ref-385219-S06542436282011021400000)
10. REPLACE FRONT SEAT ASSEMBLY LH. Refer to «REMOVAL»(ref-385219-S15042633902011021400000)
11. REPLACE LUMBAR SUPPORT SWITCH. Refer to «REMOVAL»(ref-385219-S23154430862011021400000)
12. REPLACE LUMBAR SUPPORT ADJUSTER ASSEMBLY. Refer to «REMOVAL»(ref-385219-S41550277062011021400000)
13. INSPECT SEAT VARIABLE CUSHION SWITCH Remove the seat variable cushion switch. Refer to «REMOVAL»(ref-385219-S12428176422011021400000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 2 (+B) - 5 (CSNF) Front Below 1 ohms 3 (CSNR) - 4 (E) 3 (CSNR) - 4 (R) Off 1 (E) - 5 (CSNF) 2 (+B) - 3 (CSNR) Rear 1 (E) - 5 (CSNF) NG --> See step 16 OK: Go to next step
14. INSPECT FRONT SEAT ASSEMBLY LH (VARIABLE MOTOR) Remove the front seat assembly LH. Refer to «REMOVAL»(ref-385219-S15042633902011021400000) . Check operation of the variable motor. Check if the seat cushion moves smoothly when the battery is connected to the variable motor connector terminals. OK Measurement Condition Specified Condition Battery positive (+) --> 1 Battery negative (-) --> 2 Forward Battery positive (+) --> 2 Battery negative (-) --> 1 Rearward NG --> See step 10 OK: Go to next step
15. CHECK HARNESS AND CONNECTOR (SEAT VARIABLE CUSHION SWITCH - BATTERY AND BODY GROUND) Disconnect the c36 switch connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition c36-2 (+B) - Body ground Always 11 to 14 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition c36-1 (E) - Body ground Always Below 1 ohms c36-4 (E) - Body ground NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPAIR OR REPLACE HARNESS OR CONNECTOR (SEAT VARIABLE CUSHION SWITCH - VARIABLE MOTOR)
16. REPLACE SEAT VARIABLE CUSHION SWITCH. Refer to «REMOVAL»(ref-385219-S12428176422011021400000)

When the seat memory SET switch and a seat memory switch (seat memory switch 1, seat memory switch 2 or seat memory switch 3) are pressed simultaneously, the outer mirror control ECU commands the position control ECU and switch through CAN communication to record each position value.

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With the engine switch off and the driver door closed, press the transmitter lock or unlock switch while holding a seat memory switch (seat memory switch 1, seat memory switch 2 or seat memory switch 3). Doing so will register the transmitter recognition code into the seat memory switch that was pressed. After the registration is complete, the answer-back buzzer sounds.

When a door is unlocked, the certification ECU (smart key ECU assembly) sends a door unlock signal and key ID signal to the position control ECU and switch. When the position control ECU and switch 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.