OBD Code B2305: Seat Headrest Feedback Potentiometer Circuit Short to Ground

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What This Actually Means

In plain language — no jargon

The seat headrest's position sensor is shorted to ground, like a light switch that's stuck in the ON position. The ECU can't read the actual headrest location because the electrical signal is bypassed to ground.

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Symptoms You May Notice

3 known symptoms for this code

Seat headrest position warning light or message on dashboard

Inability to adjust headrest position via controls

ECU unable to detect headrest movement or feedback

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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the potentiometer's voltage output from the headrest position sensor. A healthy sensor provides a variable voltage between ground and supply voltage as the headrest moves. When shorted to ground, the voltage collapses to 0V, indicating a circuit fault rather than actual position data.

Voltage & Parameter Thresholds

Parameter	Normal Range	Fault Condition
Potentiometer Output Voltage	0.5V to 4.5V (varies with position)	Stuck at 0V or below 0.2V (short to ground)
Sensor Resistance	1kΩ to 50kΩ (varies with position)	Near 0Ω (direct short)

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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex

1

Headrest adjustment motor wiring harness

Inspect connector pins for corrosion or moisture, clean with electrical contact cleaner and reseat firmly.

2

Headrest potentiometer sensor

Replace the faulty potentiometer if continuity testing confirms a short to ground in the sensor itself.

3

Wiring and ground straps

Check the ground wire routing for pinches or abrasions that may cause unintended contact to the signal wire.

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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B2305 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.

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How to Clear Code B2305

What happens after you fix the fault

Once the fault is repaired, B2305 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When

Fault has been diagnosed and repaired
You want to confirm the repair worked
Code appeared after a sensor was cleaned

⚠️ Do Not Clear When

Preparing for an emissions/PUC test
Root cause is still undiagnosed
Check engine light is flashing

Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.