B1392

Power Door Memory Lock Relay 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 power door lock memory relay isn't working properly, so the ECU can't control the automatic lock/unlock feature when you open or close doors. It's like a light switch that's stuck—the circuit can't complete the connection to activate the relay.

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Symptoms You May Notice

3 known symptoms for this code
Door locks don't automatically engage or disengage
Memory lock feature doesn't function when ignition turns on/off
Check Body or Service message appears on dashboard
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the voltage and current draw through the power door memory lock relay circuit. It expects specific voltage levels when commanding the relay on and off, and detects faults when resistance is abnormal or the relay fails to respond.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Relay Coil Voltage 12V when commanded on 0V or <8V when relay should activate
Circuit Resistance <1 ohm in closed state >5 ohms or open circuit
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Door lock relay connector
Inspect and clean the relay connector pins for corrosion or loose connections at the body control module.
2
Power door memory lock relay
Locate the relay in the fuse/relay box and swap it with an identical relay to test if the fault clears.
3
Wiring harness and fuses
Check the dedicated fuse for door lock circuits and inspect wiring for breaks, pinches, or burned insulation.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B1392 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 B1392

What happens after you fix the fault

Once the fault is repaired, B1392 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.