What does it mean?
B1571 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Low Voltage Differential Signal (LVDS) Video Cable Passenger .
Symptoms
- Interior lamps stay on with all doors closed and the battery goes flat
- Cluster shows a door open although the left rear door is shut and latched
- Alarm will not arm, or triggers by itself after the vehicle is locked
- Central locking refuses to lock all doors
- Door open warning appears and disappears while driving over rough roads
- On the video variant, a blank, flickering or noisy display image
Likely causes
- Worn or corroded door ajar switch, which on most designs is built into the left rear door latch
- Wiring damage in the left rear door hinge boot, where the loom flexes on every door opening
- Water reaching the latch through a torn vapour barrier, rusting the switch contacts
- Misaligned striker so the latch never reaches the fully closed position
- Corroded or partly seated connector at the latch or at the module
- Failed input in the body or rear door module
- On applications where this code refers to the video system, a damaged or unseated display cable at either end
How to fix it
- Watch the left rear door ajar status in live data while opening and closing that door by hand, and note whether the state ever changes
- Operate the latch mechanism directly with a screwdriver to separate a striker adjustment problem from an electrical fault
- Unplug the latch connector and jumper the ajar circuit to ground to confirm the module can still read a change
- Inspect the wiring inside the rear door hinge boot for broken strands, flexing it while measuring continuity
- Check the latch for water, rust and seized contacts, and inspect the vapour barrier and drains
- Replace the latch assembly if its internal switch fails a continuity test, and correct the striker alignment
- On the video variant, re-seat the cable connectors at both ends and check the cable for crushing behind the trim