What does it mean?
B1401 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Front Left Audio Speaker Output Circuit Low .
Symptoms
- No sound or weak, distorted sound from the front left speaker
- The amplifier may mute that channel, or shut down all channels to protect itself
- Sound cuts in and out as the driver door is opened and closed, if the fault is in the hinge boot
- Crackling or popping from the front left before the channel goes silent
- Balance and fader test confirms the front left is the missing corner
Likely causes
- Front left speaker voice coil shorted or partly shorted, loading the amplifier output
- Speaker wire shorted to ground where the door harness passes through the hinge boot
- Aftermarket speaker with a lower impedance than the factory amplifier is designed to drive
- Wiring pinched behind the driver door trim after speaker, window regulator or trim work
- Corroded speaker terminals after water entered the driver door
- Damaged connector or a pushed-back terminal at the amplifier or head unit plug
- Amplifier output stage failure
How to fix it
- Fade the audio fully to the front left and confirm which speaker is actually affected before opening anything
- Disconnect the speaker and measure its voice coil resistance; a reading close to zero means the speaker is shorted
- With the speaker disconnected, check the two speaker wires for a short to ground and to each other from the amplifier plug
- Flex the door hinge boot harness while listening or measuring, since that section takes all the door movement
- Remove any aftermarket speaker or adapter whose impedance does not match the factory system
- Repair the damaged wire in the boot and replace the speaker if its coil is shorted
- Replace or repair the amplifier only after the speaker and its wiring have both been proven good