Code
B1334
ALFA ROMEO
B — Body
Tailgate open circuit
Views:
UK: 3
EN: 5
RU: 2
AI status
Completed
Completed
100%
Causes
- Broken or disconnected wiring between tailgate latch/sensor and BCM
- Corroded or loose connector at tailgate latch or hinge
- Failed tailgate latch microswitch or position sensor
- Blown fuse or poor power/ground to the sensor circuit
- Water ingress or physical damage at tailgate wiring harness (hinge area)
- Aftermarket alarm/remote install damaging or interrupting the circuit
Symptoms
- Tailgate-open warning lamp or message shown on dash
- Interior or tailgate courtesy lights staying on
- Tailgate does not lock or central locking does not operate the tailgate
- Possible battery drain with tailgate circuit staying open
- Diagnostic trouble code B1334 stored in BCM
- Intermittent behavior when closing/opening tailgate (may pass on jiggle)
What to check
- Scan vehicle for stored codes and live tailgate sensor data with a diagnostic tool
- Visually inspect tailgate latch, sensor, connectors and wiring (especially through hinge grommet)
- Check for corrosion, bent pins, or water intrusion at connectors
- Verify relevant fuses and shared power/ground circuits
- Operate tailgate while watching live input; perform wiggle test on harness
- Measure supply voltage and ground at the latch connector with multimeter
Signal parameters
- Sensor supply: approximately battery voltage when ignition on (typically ~11–14 V) at the power feed to the sensor
- Closed/latched state: sensor input at BCM typically pulled to ground or near 0 V (or shows low resistance to ground)
- Open/unlatched state: sensor input typically shows battery voltage or high impedance (open circuit/infinite Ω)
- If equipped with a digital/switch signal, expect a clear change between logical low and high on the BCM input — use an oscilloscope or scan tool for intermittent traces
- Normal latch resistance (closed): low ohms; open: very high/OL — refer to service manual for exact values
Diagnostic algorithm
- Connect a scan tool, read and record freeze frame and live tailgate sensor input while operating tailgate.
- Visually inspect tailgate latch assembly, harness grommet in hinge, and connectors for damage, corrosion, or water.
- Check fuses related to body/BCM circuits. Replace if blown and retest; note if fuse blows again.
- With ignition on, back-probe the latch connector: verify supply voltage, signal voltage, and ground reference while opening/closing the tailgate.
- Perform a continuity check between the latch sensor signal pin and the BCM input pin. Inspect for short to ground or battery where present.
- Wiggle the harness through the full range of motion while monitoring the signal to reproduce intermittent open-circuit behavior.
- If open circuit in wiring is found, repair broken conductor or replace damaged section of harness (pay attention to grommet through hinge).
- If wiring and connectors are good but sensor stays open, replace the tailgate latch/sensor assembly and retest.
- If new latch and harness tested good and code persists, inspect BCM connector and grounds; consider BCM input fault and follow manufacturer procedures for module diagnosis or replacement.
- Clear codes and verify proper operation over several open/close cycles and a road test if required. Confirm no recurring codes.
Likely causes
- Wire fatigue or broken conductor in harness through tailgate hinge
- Connector pins corroded or pushed out at latch connector
- Latch sensor mechanically failed/stuck (worn microswitch)
- Open ground or fused feed to sensor due to corrosion or broken wire
- Previous body work or trunk/taillight replacement disturbed the harness
Fault status
Status
B1334 — Tailgate open circuit: the body control module detects no valid signal from the tailgate/latch position sensor (open or missing circuit). Inspect wiring, connectors, latch sensor, fuses and BCM input.
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
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