B2278 Steering shaft torque sensor fault (Ford, Mazda)

Electric power steering torque sensor malfunction

B2278 in short

On Ford and Mazda vehicles, B2278 means the electric power steering module found a fault in the steering torque sensor. Power assist may be reduced or switched off, making the wheel much heavier to turn. Ford recalled 2008–2011 Escape and Mariner models for this, so check for an open recall and get it inspected soon.

Electric power steering uses a torque sensor on the steering shaft to measure how hard you turn the wheel, and the steering module adds motor assist based on that reading. When the signal is missing or abnormal, the module stores B2278.

Ford and Mazda bulletins for the 2008–2012 Escape, 2008–2011 Mariner and 2008–2011 Tribute say B2278 is stored in the power steering control module, and that a torque sensor service kit replaces the earlier fix of a whole new steering column. Mazda later replaced its bulletin with safety recall 7614E.

Ford's recall 14V-284 says the torque sensor on 2008–2011 Escape and Mariner models may stop detecting steering input, the system may then switch off power assist, and the extra effort at low speed raises the risk of a crash. Steering is safety-critical, so this is dealer work.

Pick your make

B2278 is a manufacturer-specific code: its meaning depends on who built the car.

Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.

Most likely causes

  1. Steering shaft torque sensor fault

    Supported by vehicle data
    Why it ranks here
    Ford and Mazda bulletins name the steering shaft torque sensor for B2278 and supply a torque sensor service kit, and Ford's recall covers torque sensor faults on the Escape and Mariner.
    What would change this
    Rises on a 2008–2012 Escape, Mariner or Tribute, or if the recall is open on your VIN. Falls if the sensor signal checks good on a dealer's tool.

  2. Torque sensor wiring or connector fault

    Possible — needs testing
    Why it ranks here
    Mazda's RX-8 workshop manual lists wiring and connectors between the torque sensor and the steering module among the possible causes of B2278.
    What would change this
    Rises if the fault comes and goes or a connector is loose or corroded. Falls if the wiring tests good.

  3. Power steering control module fault or outdated software

    Possible — needs testing
    Why it ranks here
    Mazda's manual lists the steering control module as a possible cause, and Ford's recall remedy includes updating the power steering module software.
    What would change this
    Rises if the sensor and wiring test good. Falls once the sensor is confirmed faulty.
    How to test the power steering control module

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Look up your VIN on NHTSA's recall site or ask a Ford or Mazda dealer whether recall 14V-284 (Ford 14S05) or Mazda recall 7614E is open.

    Low risk

  2. Have the power steering control module codes read with a scan tool that can reach it.

    Low riskTool: scan tool with body/chassis module access

    • IfB2278 is stored in the power steering control module

      It meansThe torque sensor circuit needs a dealer diagnosis.

      Go to step 3

  3. Have a dealer or steering specialist follow the service manual diagnosis for the torque sensor and its wiring.

    Best left to a shopTool: maker's diagnostic tool

    Warning:Steering faults affect control of the car. Work on the steering column, torque sensor or steering module belongs with a dealer or steering specialist.

Symptoms

  • Power steering warning light or message on the dash
  • Steering suddenly feels heavy, especially at low speed Gets more serious: stop and have it checked.
  • Power assist cuts in and out while driving Gets more serious: stop and have it checked.

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

Parts and cost context

  • Steering torque sensor service kit:Ford and Mazda bulletins use a torque sensor kit instead of a whole new steering column. On recalled Escape and Mariner models the recall repair is free. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

  • 2008–2011 · Escape

    Supported by vehicle data

    Ford recall 14V-284 covers torque sensor faults that can remove power assist on Escapes built from August 2006 to September 2010, and a Ford bulletin replaces the torque sensor for B2278. Check your VIN for the open recall.

    Related recall campaigns: 14V284000

  • TSB-14-0016Status unverified

    B2278 stored in the power steering control module

    2008–2012escape · issued · NHTSA 10054916

    Replace the torque sensor with the service kit when B2278 is stored in the steering module. Also covers the 2008–2011 Mercury Mariner.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Mazda

  • 2008–2011 · Tribute

    Supported by vehicle data

    Mazda's bulletin for B2278 was replaced by safety recall 7614E for the electric power steering. Ask a Mazda dealer whether it is open on your VIN.

  • 06-001-14Status unverified

    B2278 (steering shaft torque sensor malfunction) in the PSCM

    2008–2011tribute · issued · NHTSA 10098045

    A torque sensor service kit corrects the condition; the steering column no longer needs replacing. Mazda later said this bulletin is superseded by safety recall 7614E.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • C0545Electric power steering torque sensor fault (GM)

    Same system Common general cause

    C0545 is GM's code for the same kind of fault: the steering torque sensor signal the electric power steering module relies on is out of range, and assist can switch off.

All Power steering and steering sensors codes

B2278 questions

Is it safe to drive with B2278?

Get it inspected soon. If the steering becomes heavy or the power steering warning comes on while driving, stop and arrange a tow or dealer visit, because Ford says losing assist raises crash risk.

Will a recall cover B2278?

On 2008–2011 Ford Escape and Mercury Mariner models, recall 14V-284 covers the torque sensor fault, and Mazda's Tribute bulletin was replaced by recall 7614E. A dealer can check your VIN.

Sources and review

  1. Recall 14V-284 (Ford 14S05): loss of electric power steering assist — Ford Motor Company / NHTSA (via carcomplaints.com) ,
  2. TSB-14-0016: B2278 stored in the power steering control module; torque sensor service kit (Escape, Mariner) — Ford Motor Company / NHTSA ,
  3. 06-001-14: DTC B2278 (steering shaft torque sensor malfunction) stored in the power steering control module (Tribute) — Mazda North American Operations / NHTSA ,
  4. RX-8 workshop manual: DTC B2278 torque sensor — Mazda Motor Corporation (mirrored by foxed.ca)
  5. Bulletin note: 06-001-14 no longer valid, superseded by safety recall 7614E (Tribute EPAS) — Mazda North American Operations / NHTSA ,
  6. 2008 Chevrolet Malibu service information: DTC C0545 — General Motors (third-party mirror)
Last reviewed
Written by
Saurabh K.
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