What Does B1406 Mean?
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected an abnormal electrical short to ground in the driver's side power window down circuit. The BCM monitors the window motor control circuits and has identified that current is flowing through an unintended path to ground, causing excessive current draw or improper circuit operation. This fault prevents normal operation of the driver's power window down function.
Common Causes
45%
Damaged or chafed wiring harness in driver's door jamb causing short to ground
30%
Failed driver power window motor with internal short to ground
15%
Faulty driver master window switch with internal short circuit
10%
Corroded or damaged BCM connector terminals causing short
Diagnostic Steps
1
Step 1: Perform visual inspection of driver door wiring harness in jamb area and throughout door. Look for chafed, pinched, or damaged wires with exposed copper touching ground. Flex harness while inspecting for intermittent shorts.
2
Step 2: Disconnect driver power window motor connector and measure resistance between the 'down' circuit terminal at the motor connector and chassis ground using a digital multimeter. Reading should be infinite resistance (open circuit). If continuity exists, wiring harness has short to ground.
3
Step 3: If wiring is intact, disconnect driver master window switch and check resistance between the 'down' output terminal and ground with switch unplugged. Infinite resistance indicates switch may be faulty. Test switch operation with multimeter in continuity mode while actuating switch.
4
Step 4: With motor and switch disconnected, back-probe BCM connector at driver window down control circuit terminal. Measure resistance to ground. Should read infinite resistance. If shorted, trace wiring between BCM and components for fault location.
5
Step 5: If all wiring checks pass, reconnect components except window motor. Using multimeter, measure resistance across window motor terminals. Typical reading is 3-12 ohms. Then check each motor terminal to motor housing (ground). Should be infinite resistance. Any continuity indicates internal motor short.
6
Step 6: After repairs, clear codes, cycle window switch through all positions multiple times, and verify code does not return. Test window operation and monitor live data for normal current draw during window operation.
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected an abnormal electrical short to ground in the driver's side power window down circuit. The BCM monitors the window motor control circuits and has identified that current is flowing through an unintended path to gr...
The most common cause of B1406 (Driver Power Window Down Circuit Short To Ground) is: Damaged or chafed wiring harness in driver's door jamb causing short to ground
Typical repair costs for B1406 range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive as this only affects power window convenience function. This is not a safety-critical issue unless window is stuck in down position during inclement weather or security concerns arise. Repair at earliest convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1406 to identify the root cause.
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Quick Info
Category
Body
System
Power Window System / Body Control
Difficulty
Type
Manufacturer
Recommended Tools
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