What this code means
B1140 may mean the door control system is not seeing the driver's power window position detection signal as expected.
What the vehicle may do
- The driver's power window may still move, but position tracking may be unreliable.
- One-touch or learned window position behavior can be affected.
- The code may return after the window is operated if the system still sees an issue.
Possible fault areas
- Possible driver's power window master switch or position detect signal concern.
- Possible connector or circuit concern in the driver's door window control area.
- Possible reset or learned-position state issue involving the power window master switch.
Diagnostic path
Code overview
On this Accord, B1140 points to a problem in the driver's power window position detect circuit. In plain terms, the door control system may not be seeing the driver's window position signal the way it expects. The window may still move, but position tracking, one-touch operation, or learned window position behavior can be affected. Broadly, this may involve the driver's power window master switch area, the position detect signal path, connector or circuit issues in the driver's door, or a switch reset state that needs to be handled correctly. For this code, keep the diagnosis tight and let the scan tool tell you which path to take.
Verify the problem first
Start by clearing the DTCs with the HDS. After that, cycle the vehicle off and back on. If it uses a key, turn the ignition switch to LOCK (0), then back to ON (II). If it uses the engine start/stop button, select OFF mode, then ON mode. Now operate the driver's power window manually from the power window master switch. Open it and close it with the switch, so the system has a chance to see the driver's window movement again.
Use the follow-up DTC check to choose the path
Next, check for DTCs again with the HDS. If related driver's power window codes are indicated, do not skip past them. Diagnose those related codes first, because they can change what B1140 is really telling you. If those related codes are not present, the next directed path is to reset the power window master switch.
Wrap-up
The key point with B1140 is not to jump straight to parts. Clear the code, cycle the vehicle, operate the driver's window manually, then let the HDS follow-up check decide whether you handle related window codes first or move to the master switch reset path. For more diagnostic training, visit stepdiagnostics.com.
Final check
Verify the code after clearing it, operate the driver's window manually, then use the follow-up HDS DTC check to decide whether to diagnose related window codes first or continue to the master switch.
For more guided automotive diagnostics, visit STEP Diagnostics.
