What does it mean?
B1573 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Short in Telephone Antenna Circuit .
Symptoms
- Door is reported permanently closed or permanently open regardless of its real position
- Interior lamps stay on, or never light for that door
- Alarm false triggers or refuses to arm
- Fuse for the rear door circuit blows
- Window or lock operation in that door becomes unreliable at the same time
- Poor phone or antenna reception on the alternate definition
Likely causes
- Ajar switch wire chafed against a 12 V feed inside the left rear door, typically the window motor, lock actuator or speaker supply
- Water bridging the circuits inside the latch or in the door connector
- Aftermarket alarm, speaker or courtesy lighting tapped into the door loom
- Latch switch shorted internally to its own feed
- Connector terminal displaced onto a powered pin
- Module input clamp damaged after the short
- On applications where this code refers to the telephone antenna, a shorted coaxial cable or antenna feed
How to fix it
- Unplug the latch and measure the ajar circuit for voltage with the ignition off: battery voltage there proves the short is in the harness
- Peel back the loom tape inside the door and inspect where it crosses the window regulator and motor
- Remove any aftermarket taps in the door and retest before condemning parts
- Check the latch for water and corrosion between its terminals
- Measure the latch switch on its own for continuity to its feed in both positions
- Repair the chafed section with proper insulation and re-route it away from the powered wires, tape alone is not a repair
- On the antenna variant, inspect the coaxial cable for a crushed or pinched section behind the trim and check the antenna feed for a short