What does it mean?
B1402 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Front Left Audio Speaker Output Circuit High .
Symptoms
- The front left speaker is silent or produces distorted sound
- The amplifier may mute the channel or go into protection and silence the whole system
- The fault can appear only when the driver window or door lock is operated, if that is the circuit feeding it
- Popping from the front left when doors are locked or windows are moved
- Radio and infotainment functions otherwise work normally
Likely causes
- Front left speaker wire chafed onto a powered circuit inside the driver door, such as a window motor or lock feed
- Aftermarket audio installation with a speaker line tapped or spliced onto a power wire
- High resistance or corroded joint in the speaker circuit, letting the output float high
- Water in the door connector bridging a speaker pin to a live pin
- Terminal pushed back in the amplifier or head unit plug and touching a powered contact
- Damaged crossover or tweeter wiring where the front left channel splits to two drivers
- Amplifier output stage failure
How to fix it
- Confirm with the balance and fader test that the front left channel is the affected one
- Disconnect the speaker and check both speaker wires for battery voltage with the ignition on, operating the windows and locks during the test
- Trace and remove any aftermarket audio splices or tapped feeds inside the driver door and behind the dash
- Inspect the door connector for water, corrosion and pushed-back terminals
- Check the harness in the hinge boot, where speaker and power wires run side by side and rub together
- On systems with a separate tweeter, check the second driver and its wiring on the same channel
- Repair the shorted or corroded wiring, retest, and replace the amplifier only if the fault stays with clean wiring and a known-good speaker