B1310

Power Door Unlock Circuit Failure

Body Chassis/Safety Power Door Locks 🟢 Low — Fix at next service ✅ Safe to Drive
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What This Actually Means

In plain language — no jargon

The vehicle's power door unlock system isn't working properly because of an electrical circuit problem. Think of it like a broken wire in your home's light switch—the signal to unlock isn't reaching the door lock actuator.

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Symptoms You May Notice

3 known symptoms for this code
Power door locks won't unlock via remote or interior button
One or more door locks remain stuck in locked position
Intermittent door unlock function that works sporadically
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The body control module monitors voltage and current in the power door unlock circuit when unlock commands are issued. It detects open circuits, short circuits, or excessive resistance that prevent proper actuator operation. The ECU expects to see voltage supplied to the unlock relay and current draw from the door lock motors when activated.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Door unlock circuit voltage 12-14V when unlock signal active Below 10V or no voltage detected
Door lock actuator current draw 2-5A during unlock operation Zero current or excessive current (short)
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Door lock actuator connector
Disconnect and reconnect the door lock motor electrical connector to clean corrosion from the pins.
2
Door unlock relay
Locate the relay in the fuse box, remove it, inspect for burnt contacts, and reinstall or replace if corroded.
3
Door lock actuator motor
Remove the door panel, disconnect the failed actuator, and install a new motor unit if electrical testing confirms no power reaches it.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B1310 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 B1310

What happens after you fix the fault

Once the fault is repaired, B1310 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.