B3A5A

Code

Generic B — Body

Active Aerodynamic Feature D Position Sensor 2 Circuit High Voltage

Brand: Generic

Type: B — Body

Views: UK: 21 EN: 32 RU: 28

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Short to battery voltage on sensor signal or reference wire
Failed/shorted position sensor (internal electronics)
Damaged wiring harness (chafing, pinched or melted insulation)
Corroded or poorly seated connector pins causing intermittent contact
Incorrect or incompatible replacement sensor
Faulty body/control module input (rare)

Symptoms

Malfunction indicator lamp (MIL) or body warning lamp illuminated
Active aerodynamic element (flap/valve/wing) not responding or stuck
Erratic or incorrect position feedback for Feature D
Vehicle may enter limited functionality for aerodynamic system
Associated codes for other aerodynamic sensors or actuators may be present

What to check

Scan for related codes and read freeze-frame data and live sensor values
Visual inspection of sensor, connector and harness for damage, corrosion, or water intrusion
Wiggle test harness and connectors while monitoring live data / code status
Backprobe sensor connector to measure signal voltage with ignition ON and device operating
Check reference (5 V) supply and ground at the sensor connector
Compare readings to known-good sensor or the other position sensors if available

Signal parameters

Typical position-sensor output: ~0.1–4.9 V DC (dependent on design); high-voltage fault when > ~4.8–5.5 V
Reference supply commonly 5 V (check vehicle-specific value) — should be stable with ignition ON
Ground continuity: near 0 Ω between sensor ground and chassis ground
If PWM-type sensor: expected duty cycle/frequency per service data; high-voltage fault if signal stuck at supply voltage

Diagnostic algorithm

Retrieve all stored codes, freeze-frame and live data. Note when fault set and conditions.
Perform a full visual inspection of the sensor, connector, and wiring for obvious damage, corrosion, or water intrusion.
With ignition ON (engine off), backprobe the sensor harness: measure reference supply voltage and sensor output. Compare to expected values and look for excessive voltage (> ~4.8–5.5 V).
Disconnect the sensor connector and measure voltage on the vehicle harness signal pin: if signal remains at battery/5 V with sensor disconnected, suspect short in wiring or module output.
Check continuity from the sensor signal pin back to the control module; inspect for short to battery with an ohmmeter (perform this with battery disconnected for wiring continuity checks).
If wiring checks good, install a known-good sensor (or bench-test original if possible) and re-check signal. If replacement cures code, original sensor was faulty.
If new sensor also shows high voltage on harness, trace/repair wiring short to power or repair connector; if wiring and connector ok, suspect control module input fault and consult module-level diagnostics/service data.
After repairs, clear codes and perform functional test of the aerodynamic feature through the scan tool and verify no recurrence.

Likely causes

Short to 12 V on the sensor signal or reference lead (most likely)
Failed position sensor (internal short to supply rail)
Corroded/loose connector at the sensor
Pinched or damaged harness near the wheel/actuator or aerodynamic device
Less likely: internal failure in the control module input

Fault status

⚠️ Status

Active Aerodynamic Feature D — Position Sensor 2 Circuit High Voltage. Sensor signal exceeded allowable voltage; inspect sensor, connector, wiring and module input for a short to battery or internal sensor failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours