B1656 — Seat Driver Rear Up Circuit Open #

Please note: The wording for DTC B1656 may vary depending on the vehicle manufacturer (OEM). Here are some known label variations for this code:

• Seat Driver Rear Up Circuit Open — Generic/OEM
• Driver Seat Rear Height Adjustment Circuit Open — Ford/Lincoln
• Driver Seat Rear Up Switch Circuit Malfunction — Toyota/Lexus
• Driver’s Power Seat Rear Up Actuator Open — Honda/Acura
• Driver Seat Height Motor Circuit Open — Nissan/Infiniti

Code summary for B1656 #

The B1656 diagnostic trouble code (DTC) refers to an open circuit condition detected in the driver’s seat rear up adjustment system. This system enables the rear portion of the seat base to tilt or raise for improved comfort and ergonomics. When the vehicle’s electronic control unit (ECU) or seat control module senses a loss of continuity or an abnormal voltage in this circuit, B1656 is stored. This code is typically associated with power-adjustable driver’s seats and can indicate anything from wiring faults to issues with the seat motor or switch. Prompt diagnosis is recommended, especially if seat adjustment is impaired.

Common symptoms for B1656 #

When B1656 is triggered, you may notice one or more of the following symptoms, often related to the function of the driver’s power seat:

• Rear portion of driver’s seat will not rise or lower
• Unusual clicking or no sound at all when pressing the seat adjustment switch
• Intermittent seat movement or seat stuck in one position
• Illuminated airbag or seat-related warning light on the dashboard
• Loss of memory seat function (if equipped)

Probable causes for B1656 (in order of frequency) #

B1656 is primarily the result of an electrical interruption or fault within the seat adjustment circuit. Here are the most common root causes, ranked by how frequently they occur:

1. Damaged or broken wiring harness to the seat adjustment motor
2. Loose, corroded, or disconnected connectors under the seat
3. Faulty seat rear up adjustment motor
4. Malfunctioning seat adjustment switch
5. Blown fuse related to the seat circuit
6. Seat control module (rarely)

Step-by-step diagnostic for B1656 #

To accurately diagnose the B1656 code, follow these professional steps. Always ensure safety by disconnecting the battery and waiting a few minutes before inspecting seat wiring, as seats may contain airbag components.

• Step 1: Scan for additional DTCs and record all seat/airbag codes present.
• Step 2: Visually inspect all wiring and connectors under the driver’s seat for obvious damage, disconnections, or corrosion.
• Step 3: Check the fuse(s) related to the power seat circuit using the owner’s manual or wiring diagram.
• Step 4: Test seat adjustment switch operation — use a multimeter to verify continuity and output when the “rear up” function is pressed.
• Step 5: Test the seat rear up motor for resistance and power supply; compare readings to OEM specifications.
• Step 6: If all components test fine, check for broken or pinched wires in the seat harness, especially in areas where the seat moves.
• Step 7: As a last resort, diagnose the seat control module (if the vehicle is equipped) for faults or software updates.

Possible repairs for B1656 #

Once the cause is pinpointed, these are the most effective repair options for resolving the B1656 code:

• Repairing or replacing damaged seat wiring harness
• Cleaning or reseating corroded or loose connectors under the seat
• Replacing the seat rear up adjustment motor if found faulty
• Replacing the seat adjustment switch if it fails continuity testing
• Replacing blown fuses and investigating underlying causes
• In rare cases, reprogramming or replacing the seat control module

Is it safe to drive with B1656? #

Yes, but with limitations. The B1656 code does not indicate a safety-critical fault, so the vehicle remains drivable. However, the driver’s seat may be stuck in an uncomfortable or unsafe position, which could impact comfort and, in rare cases, driving posture. If other airbag or seat-related codes are present, have the vehicle inspected promptly.

Vehicles most commonly affected by B1656 #

While B1656 can appear on many vehicles equipped with power-adjustable driver’s seats, it is most frequently reported on:

• Ford (F-150, Explorer, Fusion, Lincoln MKZ)
• Toyota (Camry, Avalon, Lexus ES/GS series)
• Honda/Acura (Accord, TLX, Pilot, Odyssey)
• Nissan/Infiniti (Altima, Maxima, QX60)
• Hyundai/Kia (Sonata, Santa Fe, Sorento)

Common mistakes & best practices for B1656 #

Avoid these pitfalls when diagnosing or repairing B1656:

• Replacing the motor or switch before inspecting wiring — wiring faults are more common than failed motors.
• Overlooking corroded or loose connectors under the seat, which are prone to moisture and vibration.
• Ignoring additional related DTCs, which could indicate a broader seat module or airbag issue.
• Failing to disconnect the battery before working near seat wiring (risk of accidental airbag deployment).
• Neglecting to reset the code and verify repair with a scan tool after service.

Express FAQ for B1656 #

Have more questions? Here are quick answers to common concerns:

• Q: Can I manually adjust my seat if the motor isn’t working?
  A: Most power seat systems do not allow manual adjustment if the motor or circuit is faulty. Attempting to force the seat can cause further damage.
• Q: Will B1656 cause my airbag light to stay on?
  A: Not directly. However, if the seat circuit shares wiring with seat occupancy sensors or airbag modules, an associated warning light may illuminate. Always scan for additional codes.
• Q: Is this a common problem after cleaning or moving the seat?
  A: Yes. Moving the seat to vacuum or clean underneath can tug at connectors or wiring, leading to intermittent or open circuit faults like B1656.