What this code means
B1140 may indicate a fault in the driver’s power window position detect circuit, which is associated with the door multiplex control unit area.
What the vehicle may do
- The driver’s power window may not track its position correctly.
- Auto or learned window behavior may be affected.
- The code can return after the window is operated if the system still sees the fault.
Possible fault areas
- Possible master switch or position-detect circuit concern.
- Possible wiring or connector issue in the driver’s window circuit.
- Possible door multiplex control unit communication or input concern.
Diagnostic path
Opening context
On this 2010 to 2016 Honda CR-V, B1140 points to a possible problem in the driver’s power window position detect circuit, in the door multiplex control unit area. The driver’s window may lose proper position tracking, and the issue can involve the master switch, the position-detect circuit, wiring or connector concerns, or the control unit’s ability to see the window movement correctly. The key here is not to guess at parts. First, prove whether B1140 is standing alone or whether another window-related code needs to be handled first.
Set up the problem verification
Start by clearing the codes with the HDS. After the codes are cleared, turn the vehicle OFF, to the LOCK mode, and then turn it back ON. That gives the system a clean chance to run the check again instead of chasing old stored information.
Reproduce the window movement
Next, use the power window master switch to manually open and close the driver’s power window. This is the part of the check that makes the driver’s window position signal prove itself during actual switch operation.
Read the result and choose the path
Now check for codes again with the HDS. If another related driver’s window code is present, handle that code first before continuing with B1140. If those related codes are not present, the next diagnostic move is a power window master switch reset.
Takeaway
The takeaway is simple: for B1140, clear the codes, cycle the vehicle OFF and ON, operate the driver’s window from the master switch, then recheck with the HDS. If another related window code returns, diagnose that first. If it does not, move to the power window master switch reset. For more diagnostic training, visit stepdiagnostics.com.
Final check
Confirm whether B1140 is isolated before moving forward, because related window codes may need to be diagnosed first.
For more guided automotive diagnostics, visit STEP Diagnostics.
