OBD Guide
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B3A31

Active Aerodynamic Feature Control Module D Power Mode Circuit Low Voltage

B3A31 is an OBD-II diagnostic trouble code meaning: Active Aerodynamic Feature Control Module D Power Mode Circuit Low Voltage. Common causes: weak or dead battery, alternator fault (low charging voltage). Estimated repair cost: $33–278.

Severity
✅ Low
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$33–278 (est.)

Symptoms

  • Active aerodynamics fault indicator on the panel
  • Aerodynamic elements are fixed in one position
  • Slight increase in fuel consumption
  • The general body system malfunction indicator is on
  • Error code persists after reset

Causes

  • Weak or dead battery
  • Alternator fault (low charging voltage)
  • Oxidation of the module power connector
  • Open or high resistance in the power circuit
  • Module power fuse or relay faulty

How to Fix

  1. Check battery voltage and alternator charging
  2. Read error codes and check the module supply voltage in real time
  3. Inspect the power connector of the aerodynamics module for oxidation
  4. Check the fuse and relay of the module power supply circuit
  5. Eliminate voltage loss in the circuit (charge the battery, replace the generator, repair the wiring)
  6. Reset codes and check system operation

Related codes

B3A30B3A32B3A51

Error B3A31 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the B3A31 code mean?

B3A31 is an OBD-II diagnostic trouble code that indicates: Active Aerodynamic Feature Control Module D Power Mode Circuit Low Voltage

What causes a B3A31 error code?

The most common causes of B3A31 include: Weak or dead battery; Alternator fault (low charging voltage); Oxidation of the module power connector; Open or high resistance in the power circuit.

How do I fix a B3A31 diagnostic trouble code?

To fix B3A31: Check battery voltage and alternator charging. Read error codes and check the module supply voltage in real time. Inspect the power connector of the aerodynamics module for oxidation. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B3A31?

Do not drive — repair immediately

How much does it cost to fix B3A31?

The estimated repair cost for B3A31 is $33–278. Actual cost depends on your vehicle, location, and labor rates.

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