B1309

Code

LAND ROVER B — Body

Power Door Lock - short circuit to ground Right rear fog light left rear

Brand: LAND ROVER

Type: B — Body

Views: UK: 22 EN: 26 RU: 36

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Page language: EN

Causes

Damaged or chafed wiring harness (door hinge, tailgate or body harness) contacting chassis ground
Corroded, bent or water-damaged connector at door, lock actuator or rear lamp
Shorted door lock actuator or lamp filament
Incorrect lamp or replacement part with wrong rating installed
Aftermarket accessory or modification tapping into the circuit incorrectly
Blown or shorted relay or fuse

Symptoms

Door lock(s) fail to lock or unlock, operate intermittently, or operate continuously
Rear fog light or rear lamp behaves incorrectly (stays on, flickers, or does not light)
Blown fuses related to door locks or rear lamps
Parasitic battery drain when vehicle is locked/off
BCM-related warnings or other body electrical faults present
Relevant DTC(s) stored in BCM and may return after clearing

What to check

Read and record DTCs and freeze-frame data with a diagnostic scanner; note occurrence conditions
Visually inspect door, tailgate and rear lamp connectors and wiring for damage, corrosion, moisture or pinched sections
Check fuses and relays for the door lock and rear lamp circuits; replace if blown and retest
With ignition on, command the lock/unlock or lamp ON via diagnostic tool and observe behavior
Disconnect the suspect actuator/lamp connector and see if the code clears or if circuit resistance to ground remains (isolates BCM vs load wiring)
Measure voltage at the output connector while commanding the function (watch for near 0V when it should be open, or short to ground)

Signal parameters

Supply voltage (vehicle battery): ~12 V nominal; expect battery voltage at switches/inputs when present
Driver output voltage when commanding ON: typically near battery voltage (~11–14 V) at the load; when off the output should be high-impedance/near open circuit
Short-to-ground condition: circuit shows low resistance to chassis ground (typically
Normal actuator coil resistance (typical range, vehicle-dependent): ~2–10 Ω; open circuit >>1 kΩ indicates open, near 0 Ω indicates short
Bulb/filament cold resistance may be
Expected current draw for lock actuator: typically 1–8 A (varies by design); excessive current or blown fuse suggests short or faulty motor

Diagnostic algorithm

Connect a diagnostic scanner to read all stored BCM/Body codes and note freeze-frame/occurrence conditions. Clear codes and re-run to confirm repeatability.
Visually inspect connectors and wiring for the right rear fog/left rear and door lock harness—focus on hinge areas, tailgate boot, and ground points. Repair obvious damage.
Check associated fuses and relays; replace any blown items and observe whether the code returns immediately.
Reproduce the fault: command door locks and rear fog/lamps via scanner while monitoring the circuit with a multimeter (voltage and ground). Note if the output is shorted to ground when it shouldn’t be.
Disconnect the load (unplug lamp or lock actuator connector). If the short disappears with load disconnected, suspect the load (lamp or actuator) or wiring to load. If the short persists with load disconnected, suspect wiring harness or BCM output driver.
Measure resistance from the suspect circuit pin to chassis ground with connectors removed. Low resistance indicates wiring short; open/high resistance suggests intermittent or load-related fault.
Perform a wiggle test on the harness while monitoring voltage or continuity to locate intermittent shorts. Pay attention to movement points (door hinge, boot, tailgate area).
Inspect and clean connectors; replace any with corrosion or broken seals. Repair or splice damaged wiring using correct gauge and waterproofing (heat-shrink, dielectric grease, proper terminals).
If wiring and load are good but short persists with connector disconnected, consider BCM output driver failure. Verify with manufacturer procedure; if BCM is suspected, follow immobilizer/security and programming requirements before replacement.
After repairs, clear codes, retest all functions multiple cycles, and confirm codes do not return. Record repairs and test results.

Likely causes

Wiring chafe at door hinge or tailgate causing insulation breach and contact with body ground
Corroded rear lamp connector allowing filament/connector short to chassis
Failed lock actuator coil internally shorted to ground
Water ingress in connector/boot leading to corrosion and shorting
Loose/incorrectly fitted replacement lamp or connector

Fault status

⚠️ Status

B1309 — Short to ground detected on power door lock / rear lighting circuit (right rear fog / left rear). Stored by BCM.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-3.0 hours

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B1309 — Power Door Lock - short circuit to ground Right rear fog light left rear