What Does B1656 Mean?
This code indicates that the Body Control Module (BCM) has detected an open circuit in the driver's seat rear vertical adjustment motor or its control circuit. The BCM monitors the electrical circuit that controls the upward movement of the rear portion of the driver's seat cushion and has detected a break in continuity, preventing proper seat adjustment. This is a comfort and convenience system fault that does not affect vehicle operation or safety systems.
Common Causes
40%
Broken or disconnected wiring harness to the seat motor, often caused by seat movement wearing through insulation or connector detachment
30%
Failed seat adjustment motor with open windings or internal connection failure
20%
Faulty seat switch or control module with open circuit in the switch contacts
10%
Corroded or damaged electrical connector pins at the motor or switch creating high resistance or open circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of the seat adjustment wiring harness underneath the driver's seat, checking for damaged, pinched, or disconnected wires and connectors, paying special attention to areas where the harness moves with seat travel
2
Step 2: Using a digital multimeter, test for continuity between the BCM connector (seat motor control circuit) and the seat motor connector with ignition off and connectors disconnected, expecting less than 5 ohms resistance for intact wiring
3
Step 3: Test the seat rear vertical adjustment motor directly by applying 12V power and ground to the motor terminals while disconnected from the harness, verifying motor operation in both directions
4
Step 4: Check seat switch operation using multimeter in continuity mode, activating the rear up function and verifying switch closure, expecting continuity when button is pressed
5
Step 5: Inspect all connector pins for corrosion, bent terminals, or pushed-back pins, cleaning contacts with electrical contact cleaner and ensuring proper pin engagement
6
Step 6: After repair, clear codes using scan tool, operate seat adjustment through full range of motion multiple times, and verify code does not return
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected an open circuit in the driver's seat rear vertical adjustment motor or its control circuit. The BCM monitors the electrical circuit that controls the upward movement of the rear portion of the driver's seat cushion and has detected ...
The most common cause of B1656 (Seat Driver Rear Up Circuit Open) is: Broken or disconnected wiring harness to the seat motor, often caused by seat movement wearing through insulation or connector detachment
Typical repair costs for B1656 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This fault does not affect vehicle safety or drivability and the vehicle is completely safe to operate. Repair can be scheduled at convenience, though prolonged loss of seat adjustment may affect driver comfort and proper driving position.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1656 to identify the root cause.
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Quick Info
Category
Body
System
Body Comfort and Convenience System
Difficulty
Type
Manufacturer
Recommended Tools
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