OBD Guide
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B3A51

Active Aerodynamic Feature C Position Sensor 2 Circuit Low Voltage

B3A51 is an OBD-II diagnostic trouble code meaning: Active Aerodynamic Feature C Position Sensor 2 Circuit Low Voltage. Common causes: broken position sensor power wire, signal wire short circuit to ground. Estimated repair cost: $33–167.

Severity
✅ Low
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$33–167 (est.)

Symptoms

  • Aerodynamic element C does not change position
  • Active aerodynamics system malfunction indicator is on
  • Minor change in fuel consumption
  • The general body system malfunction indicator is on
  • Error code persists after reset

Causes

  • Broken position sensor power wire
  • Signal wire short circuit to ground
  • Malfunction of the position sensor itself
  • Oxidation of the sensor connector
  • Aerodynamics control module malfunction

How to Fix

  1. Read error codes and check position sensor data in real time
  2. Check the sensor supply voltage (usually 5V from the module)
  3. Measure the signal voltage of the sensor at different positions of the element
  4. Inspect the sensor connector and wiring harness for damage.
  5. Replace the position sensor if the fault is confirmed
  6. Reset codes and check system operation

Related codes

B3A50B3A52B3A31

Error B3A51 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the B3A51 code mean?

B3A51 is an OBD-II diagnostic trouble code that indicates: Active Aerodynamic Feature C Position Sensor 2 Circuit Low Voltage

What causes a B3A51 error code?

The most common causes of B3A51 include: Broken position sensor power wire; Signal wire short circuit to ground; Malfunction of the position sensor itself; Oxidation of the sensor connector.

How do I fix a B3A51 diagnostic trouble code?

To fix B3A51: Read error codes and check position sensor data in real time. Check the sensor supply voltage (usually 5V from the module). Measure the signal voltage of the sensor at different positions of the element. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B3A51?

Do not drive — repair immediately

How much does it cost to fix B3A51?

The estimated repair cost for B3A51 is $33–167. Actual cost depends on your vehicle, location, and labor rates.

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