EN

Severity: High Code type: Manufacturer-specific (Ford)

Ford B2278 Code: Steering Shaft Torque Sensor Malfunction

The power steering module can't trust the column torque sensor, so it drops or limits steering assist.

At a glance

Severity: 4/5 – High4/5

Severity: High

Meaning
Steering Shaft Torque Sensor Malfunction
System
Body Systems · Body
Safe to drive?
With caution
Typical repair cost
$0–$2,200
DIY difficulty
Hard

On Ford vehicles with electric power assisted steering (EPAS), best known on the 2008–2012 Escape and Mercury Mariner and the closely related Mazda Tribute, the power steering control module (PSCM) reads a torque sensor on the steering column to judge how hard the driver is turning the wheel. B2278 is stored in the PSCM when that sensor's signals are missing, noisy or don't agree with each other. Because the module can no longer tell what the driver wants, it reduces or removes assist and the steering reverts to manual effort, which is heavy at parking speeds. Ford ran a safety recall on these Escape and Mariner model years for exactly this torque sensor problem, and its repair logic is specific: B2278 alone calls for a new torque sensor, while B2278 together with B1342 in the PSCM calls for a steering column assembly.

How to read B2278

How to read B2278B12223784
  1. B Body
  2. 2 Generic (SAE)
  3. 2 Body Systems
  4. 78 Specific fault

Symptoms

  • Steering suddenly becomes heavy, especially at low speed or when parking
  • Power steering fault message or wrench/AdvanceTrac warning in the cluster
  • Assist returns after the engine is shut off and restarted, then fails again
  • Steering feels notchy or pulls to one side when assist is partly reduced
  • Fault appears more often with a weak battery or on cold starts

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Failed or noisy steering shaft torque sensor on the column (the known weak point on these EPAS systems) 55%
  2. Low system voltage from a weak battery or charging problem upsetting the PSCM's sensor checks 15%
  3. Loose or corroded torque sensor connector or harness under the steering column 12%
  4. PSCM software that needs the recall or service update 10%
  5. Internal PSCM or steering column assembly failure (usually with B1342 also present) 8%

Diagnosis step by step

Diagnostic flow: B22781Check for open recalls first2Read all PSCM codes3Test the battery and charging system4Inspect the column connectors5Replace the torque sensor correctly6Calibrate and verify

  1. Check for open recalls first

    Enter the VIN on NHTSA's recall lookup or ask a Ford dealer. On covered 2008–2011 Escape and Mariner vehicles the torque sensor repair or software update may be done at no cost.

  2. Read all PSCM codes

    Use a scan tool that reaches the power steering module. B2278 alone points to the torque sensor; B2278 with B1342 (or other internal PSCM codes) points to the column assembly with its module.

    Tools: OBD-II scanner

  3. Test the battery and charging system

    EPAS draws heavy current, and a battery below about 12.4 V at rest or a charging voltage under about 13.5 V can set steering faults. Rule this out before buying steering parts.

    Tools: Multimeter

  4. Inspect the column connectors

    Remove the lower steering column cover and check the torque sensor and PSCM connectors for looseness, corrosion or pinched wires. A connector that lets go when the wheel is turned can mimic a failed sensor.

    Tools: Screwdriver, Flashlight

  5. Replace the torque sensor correctly

    The torque sensor is serviced separately on these columns, but it must be indexed exactly as the service procedure describes. A misaligned sensor causes steering pull or jerking.

    Tools: Torque wrench, Screwdriver

  6. Calibrate and verify

    After replacement, a bidirectional scan tool must run the steering torque sensor calibration so the PSCM learns the new sensor's centre. Then clear codes and road test with slow full-lock turns.

    Tools: OBD-II scanner

Where the parts are

Charging system and control modules – B22781234567
Charging system and control modules
  1. 1Battery
  2. 2Alternator
  3. 3Engine computer (ECM)
  4. 4CAN bus
  5. 5Transmission
  6. 6Wheel speed sensor
  7. 7High-voltage battery

Repair options & costs

RepairDIY?Estimated cost
PSCM software update (often covered by recall) No $0–$200
Replace battery if weak Yes $150–$320
Replace steering shaft torque sensor with calibration No $400–$1,050
Replace steering column assembly with PSCM No $1,000–$2,200

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Notes by brand

Mazda

The 2008–2011 Mazda Tribute uses the same Ford EPAS column and torque sensor as the Escape, so B2278 has the same meaning and repair on it.

Emissions / smog test impact

Depends

B2278 doesn't affect the emissions part of a US smog check. In states with a safety inspection, an active power steering warning or very heavy steering can cause a failure.

Frequently asked questions

Is it safe to drive without power steering?

You can still steer, because the column is mechanically connected to the rack, but it takes a lot of effort at low speed and the loss can happen mid-turn. Drive only short distances carefully until it's fixed.

Do I need a whole new steering column for B2278?

Usually not. On these Escape and Mariner models Ford's procedure replaces only the torque sensor when B2278 is the sole code. A column is needed when B1342 or other internal PSCM faults are also stored.

Why must the new sensor be calibrated?

The PSCM needs to learn the new sensor's zero point. Skipping the calibration can leave the steering pulling to one side or reset the fault right away.

Can a bad battery really cause B2278?

It can contribute. Electric steering is one of the biggest current users in the car, and low voltage distorts the sensor checks. Test the battery first, but don't assume it's the whole story if the code returns.

Sources