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.
DTC B1140: Driver's Power Window Position Detect Circuit Malfunction
- If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).
- Make sure you reset the power window control unit (see RESETTING THE POWER WINDOW CONTROL UNIT ) whenever you replace or substitute any power window parts.
- Clear the DTCs with the HDS.
- Turn the ignition switch to LOCK (0) and then back to ON (II), or press the engine start/stop button to select the OFF mode and then the ON mode.
- Open and close the driver's power window by using the driver's switch manually.
- Check for DTCs with the HDS.
Is DTC B1125 or B1126 indicated?
YES - Troubleshoot DTC B1125 or B1126 (see DTC B1125: DRIVER'S POWER WINDOW MOTOR A PULSE MALFUNCTION; DTC B1126: DRIVER'S POWER WINDOW MOTOR B PULSE MALFUNCTION ).
NO - Go to step 5.
- Reset the power window control unit (see RESETTING THE POWER WINDOW CONTROL UNIT ).
- Check for DTCs again with the HDS.
Is DTC B1140 indicated?
YES - Go to step 7.
NO - The system is OK at this time. Check for loose or poor connectors.
- Substitute a known-good power window master switch.
- Open and close the driver's power window by using the driver's switch manually.
- Check for DTCs with the HDS.
Is DTC B1140 indicated?
YES - Faulty the driver's power window motor; replace the driver's door regulator (see FRONT DOOR GLASS AND REGULATOR REPLACEMENT ).
NO - Faulty door multiplex control unit; replace the power window master switch (see POWER WINDOW MASTER SWITCH REPLACEMENT ).
NO RELATED
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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.