What Does B1393 Mean?
This code indicates the Body Control Module (BCM) has detected an open circuit in the power door memory lock relay circuit. This system controls the relay that locks or unlocks the power door lock memory function, typically used to store and recall driver seat and mirror positions tied to door lock operation. The BCM detected higher than expected resistance or no continuity in the relay control circuit, preventing proper relay activation.
Common Causes
35%
Failed or stuck power door memory lock relay with open internal coil or contacts
30%
Broken, corroded, or disconnected wiring between BCM and memory lock relay
20%
Corroded or loose relay socket/connector with poor contact integrity
10%
Blown fuse supplying power to the memory lock relay circuit
5%
Failed BCM with internal relay driver circuit fault
Diagnostic Steps
1
Step 1: Locate the power door memory lock relay in the fuse/relay box (typically under dash or in engine compartment). Visually inspect relay socket for corrosion, burned contacts, or physical damage. Remove relay and inspect for signs of overheating or damage.
2
Step 2: Using a digital multimeter, test the removed relay for continuity across coil terminals (should read 60-120 ohms typically) and verify contact operation by applying 12V to coil terminals while checking continuity across switch contacts.
3
Step 3: With relay removed, use multimeter to check for battery voltage at relay socket power supply pin (typically pin 30 or 87) with ignition on. Check for proper ground at relay ground pin. Measure resistance between BCM relay control pin and relay socket control terminal - should read less than 5 ohms.
4
Step 4: Inspect all wiring harness connectors between BCM and relay socket for corrosion, bent pins, or moisture intrusion. Check related fuses in the memory/accessory circuit. Wiggle test connectors while monitoring voltage/continuity.
5
Step 5: If all wiring and relay test good, perform BCM relay driver circuit test by commanding relay activation with scan tool (if bidirectional control available) while measuring voltage at relay control pin - should see switching between 0V and 12V.
6
Step 6: After repairs, clear codes, cycle ignition, operate door locks and memory seat functions multiple times, then recheck for code return to verify proper circuit operation.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an open circuit in the power door memory lock relay circuit. This system controls the relay that locks or unlocks the power door lock memory function, typically used to store and recall driver seat and mirror positions tied to door lock ...
The most common cause of B1393 (Power Door Memory Lock Relay Circuit Open) is: Failed or stuck power door memory lock relay with open internal coil or contacts
Typical repair costs for B1393 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this only affects convenience features like memory seat/mirror recall tied to door lock operation. Basic door lock and seat adjustment functions typically remain operational. Repair at convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1393 to identify the root cause.
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Quick Info
Category
Body
System
Body Control Module / Power Accessories
Difficulty
Type
Manufacturer
Recommended Tools
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