What does it mean?
B1473 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Channel 4 Audio Speaker Output Circuit Shorted Together .
Symptoms
- The channel 4 speaker goes completely silent
- The amplifier shuts that channel down or briefly drops the whole system into protection
- Sound cuts out at higher volume and returns when the volume is lowered
- The amplifier housing gets warm after playing for a while
- Code sets within seconds of switching the audio system on
Likely causes
- Loom crushed by a trim clip, screw or seat rail so both conductors meet inside the damaged section
- Insulation rubbed through where the pair crosses a sharp panel edge or passes through a grommet
- Bent spade terminal or a loose strand bridging the two tabs at the speaker
- Water and corrosion inside a connector linking the two pins
- Speaker leads twisted together or joined at a bad splice during a non-standard installation
- Internal short inside the speaker itself
- Failed amplifier output stage giving the same reading
How to fix it
- Identify the affected speaker using the fader and balance controls
- Disconnect both ends of the circuit, then measure between the two output wires with the speaker unplugged; a near-zero reading proves the harness is shorted
- If the harness is clean, measure across the speaker terminals and compare with the specified impedance to catch an internal short
- Remove trim along the route and look for crush marks, screws driven through the loom, chafe at grommets and earlier repairs
- Inspect both connectors for bent spades, stray strands and corrosion
- Repair the damaged section with proper insulation and clip the loom so it cannot be pinched again
- Replace the speaker only if the speaker itself measures shorted
- Clear the code, play at normal and high volume and confirm the channel stays on