Code
B1393
ALFA ROMEO
B — Body
Electric door memory locking relay open circuit
Views:
UK: 2
EN: 7
RU: 3
AI status
Completed
Completed
100%
Causes
- Failed/defective electric door memory locking relay
- Open or damaged wiring in relay supply or control circuit
- Corroded/loose relay connector or terminal
- Blown fuse protecting the relay circuit
- Faulty body control module (BCM) or module output stage
- Water ingress or contamination at connector or relay
Symptoms
- Door memory locking function inoperative or intermittent
- Central locking does not lock/unlock when memory command is used
- Dash message or alarm indicating locking failure
- Related convenience features (memory seats/mirrors) may not operate correctly
- DTC B1393 stored in BCM on scan tool
What to check
- Read and record freeze-frame and all stored codes with a compatible diagnostic tool
- Visually inspect relay, relay socket and nearby harness for damage, corrosion or water ingress
- Check fuses related to door locks/memory locking for continuity
- Wiggle-test harness and connectors while operating lock command to reproduce fault
- Swap relay with identical, known-good relay of same part number (if available)
- Use a multimeter to check supply voltage to the relay power terminal (should be battery voltage)
Signal parameters
- Relay supply: ~12 V battery (present at relay power pin with key on or as specified by vehicle wiring)
- Control/coil: switched 0–12 V signal from BCM (may be switched to ground or +12 V depending on design)
- When energized: relay contact continuity should be low ohms (< a few ohms) between switched terminals
- When not energized: open circuit across switched relay contacts
Diagnostic algorithm
- Connect diagnostic scanner, read and note B1393 and any related codes; clear codes and attempt to reproduce with the scan tool monitoring live data
- Verify appropriate fuses for door lock/memory circuits and replace any blown fuses
- Locate the relay in the vehicle fuse/relay box; perform visual inspection for corrosion or heat damage
- Swap the suspect relay with an identical known-good relay to see if the fault clears (if available)
- Backprobe relay socket: with the lock memory command active, verify battery voltage at supply terminal and verify a change (0V to 12V or vice versa) at the coil control terminal — if no control signal, suspect BCM or wiring
- If supply is present but relay does not energize, bench-test or substitute relay; if relay fails bench test replace it
- If relay operates but circuit downstream open, check continuity from relay output to lock actuator and to vehicle ground; repair any open wires or connectors
- Inspect and repair any damaged connectors or harness sections; clean corroded terminals and apply dielectric grease
- If wiring and relay check good but no control signal from BCM, test BCM outputs per factory procedure and consider module repair/reprogramming or replacement
- After repairs, clear codes and perform functional test of memory locking; road test and rescan to confirm code does not return
Likely causes
- Failed or internally open relay (most common)
- Broken wire or pinched harness between relay and BCM/actuator
- Corroded connector at relay or fusebox preventing continuity
- Blown fuse supplying relay coil or contacts
Fault status
Status
B1393 — Electric door memory locking relay circuit open. Check relay, fuse, wiring and BCM output.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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