B3A28
Serious Severity (Level 4)Active Aerodynamic Feature Control Module B Power Mode Circuit High Voltage
B3A28 usually means active Aerodynamic Feature Control Module B Power Mode Circuit High Voltage.
Can you still drive with B3A28?
⚠️Limited driving — get to a repair shop within 1–2 days. Avoid long trips and highway speeds.
Typical repair cost: $150 – $2000
Severity Level 4 — Serious
This code indicates a serious issue that can cause noticeable driveability problems and potential engine damage if not addressed. The vehicle should be taken to a mechanic as soon as possible. Extended driving is not recommended.
Common Symptoms
- Check Engine Light illuminated
- Engine may run rich or have poor fuel economy (PCM sees faulty signal)
- Engine control reading abnormally high or staying at maximum
- Diagnostic trouble code (DTC) stored in module memory
Possible Causes
- Failed control module — internal short causing abnormally high voltage signal to the control module
- Wiring shorted to a 5V reference or 12V power wire in the same harness — wires melted together or chafing at a common point
- Poor ground connection for the engine/body control module — high resistance in ground path causes voltage to read high
- Faulty voltage regulator or power supply within the module
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 ($7-123 at shop, free at auto parts store for basic scan)
- Visually inspect the engine/body control module wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $77 diagnostic fee at shop)
- Test control module with a multimeter at the connector — compare readings to factory service manual specs. If out of spec, replace control module ($150-2000)
- Check the reference voltage supply to control module — should be steady 5V (or 12V) — if low, trace back to PCM/BCM voltage regulator ($123-597 if module repair needed)
- Perform a voltage drop test on the ground side of the engine/body control module circuit — more than 0.1V drop means a bad ground that must be cleaned/repaired ($75-236 at shop)
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 B3A28 mean?
B3A28 stands for "Active Aerodynamic Feature Control Module B Power Mode Circuit High Voltage". B3A28 usually means active Aerodynamic Feature Control Module B Power Mode Circuit High Voltage.
Can you drive with B3A28?
Limited driving — get to a repair shop within 1–2 days. Avoid long trips and highway speeds.
How much does it cost to fix B3A28?
Repair costs for B3A28 typically range from $150 to $2000, 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 ($7-123 at shop, free at auto parts store for basic scan); Visually inspect the engine/body control module wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $77 diagnostic fee at shop); Test control module with a multimeter at the connector — compare readings to factory service manual specs. If out of spec, replace control module ($150-2000).
Will B3A28 clear itself?
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