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.
Inspection Procedure
- PERFORM ACTIVE TEST (POWER WINDOW UP/DOWN)
- Select the ACTIVE TEST, use the intelligent tester to generate a control command, and then check the power window.
Multiplex network master switch assembly:
DIAGNOSIS NOTE CHARTItem Test Details Diagnostic Note PAN UP/ DOWN Power Window UP/DOWN - OK:
Driver side power window operates normally.
CAUTION: Be careful to avoid injuries as this test causes vehicle parts to move.
NG: Go to step 2
OK: REPLACE MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY
- Select the ACTIVE TEST, use the intelligent tester to generate a control command, and then check the power window.
- READ VALUE USING INTELLIGENT TESTER
- Check the DATA LIST for proper functioning of the power window master switch.
Multiplex network master switch assembly
DIAGNOSIS NOTE CHARTItem Measurement Item/ Display (Range) Normal Condition Diagnostic Note P/W UP SW Driver side power window
UP switch signal/ ON or OFFON: Driver side power window switch UP operates
OFF: Driver side power window switch UP does not operate- P/W DOWN SW Driver side power window
DOWN switch signal/ ON or OFFON: Driver side power window switch DOWN operates
OFF: Driver side power window switch DOWN does not operate- OK:
ON (switch operates) appears on screen.
NG: REPLACE MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY
OK: Go to next step
- Check the DATA LIST for proper functioning of the power window master switch.
- INSPECT FUSE (FR DOOR LH, LH-IG, AM2, D/C CUT, MPX-B)
- Remove the FR DOOR LH, LH-IG fuses from the cowl side junction block LH.
- Remove the AM1 fuse from the cowl side junction block RH.
- Remove the MPX-B and D/C CUT fuses from the engine room No. 1 Relay Block.
- Measure the resistance of the fuses.
Standard resistance:
Below 1 Ω
NG: REPLACE FUSE
OK: Go to next step
- CHECK WIRE HARNESS (MASTER SWITCH ASSEMBLY - FRONT MOTOR ASSEMBLY LH (DRIVER SIDE))
- Disconnect the Q13 switch connector.
- Disconnect the M11 motor connector.
- Measure the resistance of the wire harness side connectors.
Standard resistance
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition Q13-1 (DUP) - M11-2 (U) Below 1 Ω Q13-11 (DDN) - M11-1 (D) Below 1 Ω Q13-1 (DUP) or M11-2 (U) - Body ground 10 kΩ or higher Q13-11 (DDN) or M11-1 (D) - Body ground 10 kΩ or higher
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
- CHECK WIRE HARNESS (MASTER SWITCH ASSEMBLY - FRONT DOOR ECU LH AND BATTERY)
- Disconnect the Q13 switch connector.
- Disconnect the M9 ECU connector.
- Measure the voltage and resistance of the wire harness side connectors.
Standard voltage
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition Q13-9 (CPUB) - Body ground 10 to 14 V Standard resistance
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition Q13-10 (BDR1) - M9-5 (BDRJ) Below 1 Ω Q13-20 (SIG) - M9-10 (SIGJ) Below 1 Ω Q13-2 (E) - M9-2 (PWE) Below 1 Ω Q13-10 (BDR1) or M9-S (BDRJ) - Body ground 10 kΩ or higher Q13-20 (SIG) or M9-10 (SIGJ) - Body ground 10 kΩ or higher Q13-2 (E) or M9-2 (PWE) - Body ground 10 kΩ or higher
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
- CHECK WIRE HARNESS (FRONT DOOR ECU LH - BATTERY AND BODY GROUND)
- Disconnect the M9 ECU connector.
- Measure the voltage and resistance of the wire harness side connector.
Standard voltage
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Condition Specified Condition M9-4 (CPUB) - Body ground Always 10 to 14 V M9-6 (BDR) - Body ground Always 10 to 14 V M9-3 (SIG) - Body ground Engine switch on (IG) 10 to 14 V Standard resistance
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Condition Specified Condition M9-1 (GND) - Body ground Always Below 1 Ω
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
- CHECK WIRE HARNESS (FRONT DOOR ECU LH (SEL1 - SELE))
- Disconnect the M10 ECU connector.
- Measure the resistance of the wire harness side connector.
Standard resistance
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition M10-11 (SEL1) - M10-12 (SELE) Below 1 Ω M10-11 (SEL1) or M10-12 (SELE) - Body ground 10 kΩ or higher
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
- INSPECT POWER WINDOW REGULATOR MOTOR ASSEMBLY LH FRONT
- Remove the motor.
- Apply battery voltage to connector terminals 1 and 2.NOTE: Do not apply battery voltage to any terminals except terminals 1 and 2.
- Check that the motor gear rotates smoothly as follows.
OK
MEASUREMENT CONDITION CHARTMeasurement Condition Specified Condition Battery positive (+) → 1
Battery negative (-) → 2Motor gear rotates counterclockwise Battery positive (+) → 2
Battery negative (-) → 1Motor gear rotates clockwise
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE FRONT POWER WINDOW REGULATOR MOTOR ASSEMBLY LH
OK: Go to next step
- CHECK OPERATION OF MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY
- Temporarily replace the multiplex network master switch assembly with a new or normally functioning one.
- Check that the power window operates normally.
OK:
Power window operates normally.
NG: REPLACE FRONT MULTIPLEX NETWORK DOOR ECU LH (DRIVER DOOR ECU)
OK: END (MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY IS FAULTY)
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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.
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