Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Only Wireless Control Function is Inoperative: Procedure
- CHECK WIRELESS CONTROL FUNCTION
- Check whether the wireless control function operates correctly when using a different seat control transmitter.RESULT
Result Proceed to Wireless control function operates correctly A Wireless control function does not operate correctly B
B → See step 4
A: Go to next step
- Check whether the wireless control function operates correctly when using a different seat control transmitter.
- REPLACE TRANSMITTER BATTERY
- Replace the transmitter battery of the non-working seat control transmitter with a new battery or a battery that is known to be good. Refer to REPLACEMENT .
NEXT: Go to next step
- CHECK TRANSMITTER BATTERY
- Confirm that the red LED of the seat control transmitter comes on when the ingress switch or egress switch of the seat control transmitter are pressed.RESULT
Result Proceed to Come on A Do not come on B
B → REPLACE SEAT REMOTE CONTROL SWITCH SET (SEAT CONTROL TRANSMITTER)
A → END (TRANSMITTER BATTERY IS DEFECTIVE)
- Confirm that the red LED of the seat control transmitter comes on when the ingress switch or egress switch of the seat control transmitter are pressed.
- CHECK HARNESS AND CONNECTOR (SEAT CONTROL RECEIVER - BATTERY AND BODY GROUND)
- Disconnect the K21 seat control receiver connector.
- Measure the voltage and resistance according to the value(s) in the table below.
Standard
Tester Connection Condition Specified Condition K21-5 (+B) - Body ground Always 11 to 14 V K21-1 (GND) - Body ground Always Below 1 Ω TEXT IN ILLUSTRATION*a Front view of wire harness connector
(to Seat Control Receiver) - Reconnect the seat control receiver connector.
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- HARNESS AND CONNECTOR (POSITION CONTROL ECU ASSEMBLY - SEAT CONTROL RECEIVER)
- Disconnect the Q2 position control ECU assembly connector.
- Disconnect the K21 seat control receiver connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition Q2-21 (PRG) - K21-3 (SGIN) Always Below 1 Ω Q2-21 (PRG) - Body ground Always 10 kΩ or higher - Reconnect the seat control receiver connector.
- Reconnect the position control ECU assembly connector.
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- CHECK POSITION CONTROL ECU ASSEMBLY
- Measure the voltage and check for pulses according to the value(s) in the table below.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Standard Voltage
Tester Connection Switch Condition Specified Condition Q2-21 (PRG) - Body ground Seat control transmitter (ingress switch) off → on 11 to 14 V → Pulse generation TEXT IN ILLUSTRATION*a Component with harness connected
(Position Control ECU Assembly)
NG → See step 7
OK → See step 8
- Measure the voltage and check for pulses according to the value(s) in the table below.
- REPLACE SEAT REMOTE CONTROL SWITCH SET (SEAT CONTROL RECEIVER). Refer to REMOVAL
- REPLACE POSITION CONTROL ECU ASSEMBLY. Refer to DISASSEMBLY
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.