B3A58

Code

Generic B — Body

Active Aerodynamic Feature D Position Sensor 1 Circuit High Voltage

Brand: Generic

Type: B — Body

Views: UK: 24 EN: 35 RU: 25

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Page language: EN

Causes

Short to battery on the position sensor signal circuit
Damaged or chafed wiring harness causing voltage injection
Corroded or poor connector/pin contact at sensor or module
Failed/shorted position sensor (internal electronics)
Faulty body or aerodynamic control module (rare)
Aftermarket accessories or improper jump-start wiring introducing over-voltage

Symptoms

Malfunction lamp (MIL) or body warning lamp illuminated
Active aerodynamic feature may be inoperative, stuck, or default to a safe position
Stored fault code B3A58 (Position Sensor 1 Circuit High Voltage) in module
Erratic or out-of-range position reading in live data (very high voltage)

What to check

Read and record freeze frame and permanent data with a scan tool
Retrieve related codes for other aerodynamic/position sensors and communication errors
Visually inspect wiring and connectors for damage, corrosion, pin push-out, or water ingress at the sensor and control module
Check for recent battery work or aftermarket additions that could affect wiring
Backprobe the sensor connector and measure signal voltage with ignition ON (engine off)
Measure reference supply voltage (usually ~5 V) and sensor ground continuity

Signal parameters

Expected signal voltage: typically ~0.5–4.5 V (check vehicle-specific spec)
Reference supply: typically +5 V (key ON, engine off)
High-voltage fault threshold: signal > reference + tolerance (often >5.5 V)
Ground continuity: near 0 ohms to chassis ground from sensor ground circuit

Diagnostic algorithm

Connect a capable scan tool, confirm B3A58 is present and record freeze frame/live data for Position Sensor 1.
Visually inspect sensor connector, harness routing, and aerodynamic actuator for damage, corrosion, pin deformation, or foreign matter. Repair or clean as needed.
With ignition ON (engine off), backprobe the sensor connector: measure reference supply voltage, signal voltage, and sensor ground. Compare to vehicle specifications. If signal is above reference or >5.5 V, proceed.
If signal is high, disconnect the sensor connector. Re-measure voltage on the harness signal terminal (connector still connected to harness). If the high voltage remains with sensor disconnected, suspect short to battery or accessory feed—inspect harness for short to 12 V.
If signal voltage is normal with sensor disconnected, test the sensor separately (bench test if possible) or substitute known-good sensor. Replace sensor if it outputs high or erratic voltage when powered per spec.
Check wiring continuity between sensor signal/ground and the aerodynamic control module. Repair any opens, shorts-to-power, or shorts-to-ground found. Pay attention to harness areas that move with the aerodynamic component.
If wiring and sensor test good, inspect/replace the aerodynamic control module or vehicle body control module per manufacturer procedures. Verify no other modules are back-feeding voltage.
Clear codes and perform a function test and verify the fault does not return; road test if required by the procedure.