B1393 — Power Door Memory Lock Relay Circuit Open

How do I diagnose B1393 myself?

Start with a scan: confirm B1393, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the power door memory lock relay, and verify the suspect component against live data before buying parts.

What does OBD2 code B1393 mean?

B1393 — Power Door Memory Lock Relay Circuit Open. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: damaged wiring in door jambs or wet areas, body control module (BCM) fault, corroded or loose connectors.

Will B1393 clear itself?

Sometimes B1393 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What is the most common cause of B1393?

The most common causes are: damaged wiring in door jambs or wet areas, body control module (BCM) fault, corroded or loose connectors.

What are the symptoms of B1393?

Drivers most often notice: warning light on the dashboard, no impact on engine operation in most cases, the affected function (locks, windows, lighting, wipers) works intermittently or not at all.

Code B1393 triggers when a vehicle's body control module detects that the power door memory lock relay circuit has lost electrical continuity. The term "circuit open" tells you exactly what the diagnostic system found: somewhere along the path that supplies power to the door memory lock relay, current can no longer flow. Without that complete electrical path, the module cannot command the lock mechanism to operate as programmed.

The power door memory lock relay is part of your vehicle's body electrical architecture. It sits between the body control module and the door lock actuators, handling the heavy current draw when you lock or unlock the doors. When this relay circuit develops an open condition—due to a broken wire, corroded connector, blown fuse, or failed component—the module stores B1393 because it can no longer reliably control the door locks.

The module does not log B1393 from a single glitch. Automotive diagnostics require a fault to appear consistently under defined operating conditions before the check engine light activates and freeze frame data is captured. That snapshot—engine load, RPM, coolant temperature, vehicle speed—tells you exactly what was happening when the fault occurred, giving you a target to replicate during testing.

Common symptoms of B1393

• Dashboard warning light or indicator lamp illuminated
• Engine, transmission, and braking systems operate normally in most cases
• One or more door lock functions fail to respond to switch commands
• Door locks operate intermittently or unpredictably
• Affected function may stop working entirely until the fault is resolved
• In some configurations, related systems such as power windows, interior lighting, or windshield wipers may also be affected

What causes B1393?

• Broken or severed wire within the power door memory lock relay harness
• Connector that has backed out of its socket, has a pushed-out pin, or shows heavy corrosion on the terminals
• Internally failed power door memory lock relay
• Blown fuse protecting the door lock circuit
• Faulty body control module unable to properly manage the circuit
• Failed door lock switch, motor, or actuator
• Corroded or loose electrical connectors anywhere along the circuit
• Wiring damage in door jambs or areas exposed to moisture

How to diagnose B1393

1. Connect an OBD2 scanner, retrieve all stored codes, and record the freeze frame data associated with B1393. This data pinpoints the engine conditions present when the fault was detected.
2. Look for related diagnostic trouble codes that may point to the root cause rather than the symptom. Check for manufacturer technical service bulletins covering your specific make and model—many body electrical issues have documented fixes or software updates available.
3. Perform a thorough visual inspection of the wiring harness and connectors tied to the door lock circuit. Look for damaged insulation, green or white corrosion buildup, and any wires that have pulled free from their terminals.
4. Use a multimeter to check continuity end-to-end on the power door memory lock relay circuit. Apply light pressure and wiggle the harness during testing—intermittent opens will show as fluctuating or open readings only when the wire is moved.
5. Operate the door lock switch while observing live data on the scanner, watching the status PIDs for the switch input and motor output to confirm signals reach and leave the control module.
6. Examine all connectors and wiring at flex points, particularly the door jamb pass-throughs and hinge areas where repeated movement causes wires to fatigue and break.
7. Clear B1393, complete a full drive cycle that recreates the conditions from the freeze frame data, and verify the code does not return.

How to fix B1393

Address the most common and least expensive failure points before pursuing costly component replacement:

• Body control module repair or replacement: $300–$900
• Wiring harness repair or connector replacement: $80–$250
• Door lock switch or actuator replacement: $120–$450

How much does it cost to fix B1393?

The actual repair cost depends entirely on which component in the door lock circuit failed. Here are typical scenarios including parts and labor at independent shop rates:

• Body control module repair or replacement: $300–$900
• Wiring harness repair or connector replacement: $80–$250
• Door lock switch or actuator replacement: $120–$450

In most cases, fixing B1393 costs between $80 and $900 depending on root cause. An accurate diagnosis before purchasing parts is the single most effective way to keep total costs down—the body control module replacement at the high end is rarely the first thing to check.

Can you drive with B1393?

In most situations, B1393 presents no drivability concern—this code belongs to the body electrical system, not the engine or drivetrain. Your vehicle will start, accelerate, steer, and brake normally. However, a few scenarios deserve attention: if the malfunction affects exterior lighting, driving at night or in poor weather becomes hazardous; if wipers fail during a storm, visibility drops dangerously; and a central locking system that leaves the doors unsecured poses a security risk. While the vehicle remains operationally safe to drive, addressing the underlying electrical fault promptly restores full functionality and eliminates potential safety gaps.

Related OBD2 codes

• B1300: Power Door Lock Circuit Failure
• B1301: Power Door Lock Circuit Open
• B1302: Accessory Delay Relay Coil Circuit Failure
• B1303: Accessory Delay Relay Coil Circuit Open
• B1304: Accessory Delay Relay Coil Circuit Short To Battery
• B1305: Accessory Delay Relay Coil Circuit Short To Ground