What does it mean?
B1406 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Front Right Audio Speaker Output Circuit High .
Symptoms
- Front right speaker silent or badly distorted
- The amplifier may mute the channel or drop into protection and silence the whole system
- The fault can appear only while the passenger window or the door locks are operated
- Popping from the front right when windows or locks are used
- Every other audio and infotainment function works normally
Likely causes
- Front right speaker wire chafed onto a powered circuit inside the passenger door, such as a window motor or lock feed
- Aftermarket audio wiring spliced or tapped into a power wire on that channel
- Corroded, high resistance joint in the speaker circuit letting the output float high
- Water in the passenger 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
- Faulty crossover or tweeter wiring where the front right channel splits to two drivers
- Amplifier output stage failure
How to fix it
- Use the fader and balance test to confirm the front right channel is the faulty 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 splices or tapped feeds in the passenger door and behind the dash
- Inspect the passenger door connector for water, corrosion and pushed-back terminals
- Check the harness in the hinge boot, where speaker and power wires run together and can rub through
- On systems with a separate tweeter, test that driver and its crossover on the same channel
- Repair the wiring, retest with a known-good speaker, and replace the amplifier only if the high reading remains