B1660 — Seat Driver Front Up Circuit Open

Overview of the code

The diagnostic trouble code B1660 refers to an open circuit problem in the driver’s side front seat adjustment electrical system. Essentially, it indicates that the vehicle’s ECU (Electronic Control Unit) has detected an interruption or disconnection in the wiring or connector responsible for the seat’s upward movement function.

Please note that labeling of this code can vary between manufacturers, and some OEMs might use different codes or descriptions for similar faults.

Fast Facts

  • System affected: Seat adjustment motor circuit
  • Severity: Moderate
  • Main symptoms: Seat adjustment failure, warning light
  • Driveability: No — the seat adjustment feature may be unavailable, but the vehicle can typically be driven safely

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Manufacturer variations for trouble code B1660

Different vehicle manufacturers may assign unique labels or code formats for similar faults involving the driver’s seat adjustment circuit. The B1660 code, in particular, might be referenced differently depending on the OEM.

Common variations include:

  • Volkswagen (VW), Audi: 5F0 959 791, 8K0 959 791
  • Ford: C1223
  • General Motors (Chevrolet, Opel): U0132
  • Others: Some manufacturers may use a « body control module » (BCM) fault code related to seat electronics

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What does trouble code B1660 mean?

Trouble code B1660 indicates that the vehicle’s ECU has detected an open circuit in the driver’s seat upward adjustment wiring.

In simpler terms, the ECU is monitoring the electrical circuit that allows the seat to move upward and has identified a break, disconnection, or faulty wiring, causing the circuit to be incomplete.

This usually happens when the internal wiring has been damaged, disconnected, or a connector has come loose. The problem could also stem from a failed seat adjustment switch or motor.

This code is typically set when the ECU notices that it cannot complete the electrical loop needed to activate the seat’s upward movement process.

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Severity and risks of trouble code B1660

The B1660 code, generally classified as a moderate fault, mainly affects the automatic seat adjustment feature. Importantly, it does not usually impact vehicle safety or drivability on its own.

However, if the seat cannot be adjusted, especially for drivers with specific ergonomic needs, this can cause discomfort, or even compromise driving position and control, particularly if the seat is part of a memory system.

It is recommended to address this fault promptly to restore full seat operability, but the vehicle can typically be driven safely in the meantime.

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Symptoms of trouble code B1660

When this code appears, you may notice specific symptoms related to the seat adjustment system, such as:

  • Inability to move the seat upward
  • Warning lights or messages on the dashboard indicating seat adjustment issues
  • Intermittent seat operation
  • Unusual clicking sounds from the seat area if internal motor or switch issues exist
  • Manual seat adjustment still functional but electronic upward adjustment is unavailable

Some drivers might also observe that the seat adjustment controls do not respond at all, or that there are warning indicators related to seat control.

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Most likely causes of trouble code B1660

This fault usually results from issues within the electrical circuit controlling the seat’s upward movement. The most common causes include:

  1. Broken or damaged wiring or connectors in the seat circuit — the wiring harness may be frayed, pinched, or corroded over time.
  2. Faulty seat adjustment switch or control module that no longer completes the circuit properly.

    3. 3. Defective seat motor or actuator — although less common, a malfunctioning motor can sometimes trigger a circuit open if the ECU detects an abnormality.

    4. Electrical grounding issues — poor grounding connections can lead to intermittent or open circuits.

    5. Internal wiring fault within the seat’s wiring harness or connectors, especially if the seat has been recently repaired or damaged in an accident.

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How to diagnose trouble code B1660

Diagnosing this fault involves a systematic check of the seat’s electrical circuit. The process should be conducted carefully to avoid unnecessary component replacement.

A typical diagnostic process may include:

  1. Visual inspection of wiring harnesses, connectors, and seat wiring for obvious signs of damage, corrosion, or loose connections.
  2. Check the seat switch and control module for any visible damage or signs of wear.
  3. Test electrical continuity of the wiring circuit using a multimeter to ensure there are no opens or shorts.
  4. Use a scan tool to view live data and verify whether the seat adjustment switch is sending signals when operated.
  5. Manually activate the seat motor and check for voltage at the connector, ensuring power delivery to the motor.

Always refer to the specific vehicle-specific wiring diagrams and repair manuals when performing these diagnostics.

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Possible repairs for trouble code B1660

Addressing this trouble code involves restoring circuit integrity and replacing faulty components. Typical repairs include:

  • Repair or replace damaged wiring or connectors. (Basic repair, often DIY if wiring damage is visible and accessible)
  • Replace the faulty seat adjustment switch or control module. (Professional repair recommended for electronic components)
  • Repair or replace the seat motor or actuator if diagnosed as defective, especially if internal wiring has failed.
  • Secure or replace grounding points to ensure proper electrical grounding.
  • Perform dashboard or software reset after repairs to clear fault codes (requires diagnostic tool).

In some cases, especially with wiring or module issues, professional diagnosis and repair are recommended to ensure proper functionality and safety.

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Vehicles commonly associated with trouble code B1660 in Europe

While the exact occurrence of this fault code varies, it has been reported in several vehicle models across brands, particularly those with electrically adjustable seats.

Typically, vehicles from major manufacturers with integrated electronic seat adjustment systems are affected, such as:

  • Volkswagen Group (Volkswagen, Audi, SEAT, Škoda): Many models with electrical seats
  • Ford
  • General Motors (Chevrolet, Opel, Vauxhall)
  • Other brands with electrically powered seat adjustments

Specific engine families are less relevant here, as the fault relates primarily to seat wiring and components.

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Frequent mistakes with trouble code B1660

Diagnosing and repairing this fault can sometimes lead to common errors, such as:

  • Assuming the problem is solely with the motor or switch, without inspecting wiring or connectors.
  • Neglecting to perform a proper visual inspection before testing electronic components.
  • Using incorrect or non-specific testing procedures, leading to misdiagnosis.
  • Replacing components prematurely without verifying the actual cause, resulting in unnecessary costs.
  • Ignoring secondary wiring or grounding issues that could be the underlying cause of the open circuit.

Adopting a methodical approach and verifying each potential cause step-by-step helps avoid these mistakes.

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FAQ — trouble code B1660

Can this code disappear on its own? Typically, no. This fault is related to a physical or electrical issue that needs repair. Sometimes, a loose connector or temporary wiring problem can clear if fixed, but the fault will usually reappear unless addressed.

Can I keep driving? In most cases, yes. Since this code affects the seat adjustment system and not critical vehicle functions, you can drive as long as the seat position is acceptable. However, for comfort and to prevent further damage, repair is advised.

Why does the code return after clearing? If the underlying cause — such as damaged wiring, a faulty switch, or motor — isn’t repaired, the code will likely reappear once the system performs its self-test. Proper diagnosis and repair are essential to prevent recurrence.

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