B3A40
Low Severity (Level 2)Active Aerodynamic Feature B Actuator Temperature Not Plausible
B3A40 usually means active Aerodynamic Feature B Actuator Temperature Not Plausible.
Can you still drive with B3A40?
⚠️Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
Typical repair cost: $50 – $600
Severity Level 2 — Low
This code indicates a minor issue that is unlikely to cause immediate driveability problems. You can typically continue driving but should have the vehicle inspected at your earliest convenience.
Common Symptoms
- Warning light or malfunction indicator related to the body electrical system is illuminated
- The body electrical system is not operating as designed
- Diagnostic trouble code (DTC) stored in module memory
- Fault may be intermittent — code may clear itself and reappear
- Reduced vehicle functionality related to the body electrical system
Possible Causes
- Faulty body control module or wiring — most common cause, test before replacing
- Damaged or corroded wiring/connector in the body electrical system circuit
- Blown fuse or faulty relay for the body electrical system
- Poor ground connection — check and clean all related ground points
- Control module fault — rare but possible, only consider after ruling out simpler causes
Common Fixes
- Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($11-149 at shop, free at auto parts store for basic scan)
- Visually inspect the body electrical system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $122 diagnostic fee at shop)
- Replace body control module or wiring if testing confirms it has failed — use OEM quality, avoid the cheapest no-name aftermarket parts that fail in a year ($50-600)
- Check and replace any blown fuses in the body electrical system fuse circuit — if fuse blows again, there's still a short that needs to be found ($1-10 for fuses)
- Perform a wiggle test on the body electrical system wiring harness while monitoring live data — see if the fault returns when you move the harness at different points ($0-137 diagnostic labor)
Estimated Repair Cost
These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.
Frequently Asked Questions
What does B3A40 mean?
B3A40 stands for "Active Aerodynamic Feature B Actuator Temperature Not Plausible". B3A40 usually means active Aerodynamic Feature B Actuator Temperature Not Plausible.
Can you drive with B3A40?
Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
How much does it cost to fix B3A40?
Repair costs for B3A40 typically range from $50 to $600, depending on your vehicle make, model, and local labor rates. Common fixes include: Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($11-149 at shop, free at auto parts store for basic scan); Visually inspect the body electrical system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $122 diagnostic fee at shop); Replace body control module or wiring if testing confirms it has failed — use OEM quality, avoid the cheapest no-name aftermarket parts that fail in a year ($50-600).
Will B3A40 clear itself?
Explore Repair Costs
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