Code
B1393
FIAT
B — Body
Electric door memory locking relay open circuit
Views:
UK: 3
EN: 6
RU: 2
AI status
Completed
Completed
100%
Causes
- Open or broken wiring in the relay supply or control circuit
- Poor or corroded connector(s) at the relay, fuse, or BCM
- Failed (open) door memory locking relay
- Blown fuse or fusible link feeding the relay
- Faulty Body Control Module (BCM) driver or internal connector fault
- Water intrusion or physical damage in the door/relay area
Symptoms
- Door memory locking function (memory lock/unlock) does not operate
- Central locking works intermittently or not at all for memory function
- DTC B1393 stored in BCM or instrument cluster
- No clicking sound from relay when lock/unlock memory is commanded
- Other body electrical anomalies nearby (intermittent locks, water-damaged connectors)
What to check
- Read live data and attempt to actuate door memory locking via scan tool while watching for changes and code set events
- Visually inspect relay, socket, and harness for corrosion, damage, or loose pins
- Check relevant fuses and fusible links for continuity
- Check supply voltage at relay power terminal (should be battery voltage, ~11–14 V)
- Check control/driver signal at relay coil terminal while commanding the function (BCM should provide switching voltage or ground)
- Measure relay coil resistance with relay removed (compare to specification or swap with identical known-good relay)
Signal parameters
- Relay supply voltage: approximately 11–14 V with ignition on or as specified by vehicle documentation
- Coil control signal: either switched ground or switched +12 V from BCM; when commanded coil should show near 12 V across coil terminals (energized) or near 0 V across coil when de-energized, depending on circuit type
- Typical relay coil resistance (general guide): ~50–200 ohms (varies by relay type) — consult vehicle spec
- Contact continuity when relay energized:
- Contact open when de-energized: effectively infinite/open circuit between common and NO
Diagnostic algorithm
- Confirm code and freeze frame with a diagnostic scanner. Note conditions when code set (ignition state, door states).
- Inspect relay, relay socket, and harness for signs of corrosion, damage, or moisture. Check mounting area for water ingress.
- Check related fuses and power feed(s) for continuity and correct voltage; replace any blown fuses and retest.
- Attempt to actuate the door memory locking function from a scan tool while listening for relay operation. If relay does not click, proceed.
- Probe the relay socket: with ignition on and command active, measure supply at relay power terminal and measure control terminal for switching (voltage or ground). Record voltages.
- If supply is present but control signal is absent, trace continuity from BCM output to relay coil. Repair any open circuit or connector fault.
- If control signal is present but relay does not energize, remove relay and measure coil resistance. If coil open or out of spec, replace relay.
- If relay bench-tests good and wiring is good, inspect BCM driver output for damage. If BCM output is inconsistent or shorted, consider module diagnosis/reprogramming/replacement following manufacturer procedures.
- After repairs, clear codes, perform functional test of memory locking, and verify no return of fault. Document wiring repairs and any replaced parts.
Likely causes
- Relay failed open
- Connector corrosion or pin pushed out at relay socket
- Broken wire between relay and BCM or between relay and actuator
- Blown fuse feeding the relay
Fault status
Status
Open circuit detected in electric door memory locking relay circuit. Relay coil or contacts not completing circuit; BCM stored fault. Inspect relay, supply/fuse, connectors, and wiring.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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