Body, generic

B0123 Pedestrian Alert Speaker B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0123 is the same check for pedestrian alert speaker B, which implies a second sounder. Ford's special service message 48451 for 2020 hybrids and plug-ins describes speakers at the front and the rear that sound in forward and reverse between 0 and 30 km/h. In the EU, Regulation 540/2014 made an acoustic vehicle alerting system compulsory on all new hybrid and electric vehicles from July 2021, sounding from start-up to about 20 km/h and when reversing. Stellantis records internal faults of its quiet vehicle pedestrian module as B2779-04, a maker-specific code rather than this one. No manufacturer links B0123 to a particular speaker in public; with B silent, one direction loses its warning and the legal sound requirement is no longer met.

Likely causes

Speaker B defective, for example from moisture in the rear bumper or wheel arch area
Loose or corroded connector at speaker B or a rattling internal connector at the module
Fault in the sound generator module or its software

Symptoms

  • Artificial sound missing at the front or rear, e.g. only audible when moving off forwards
  • Possible warning message about the pedestrian alert system
  • Legally required warning sound incomplete; have it repaired soon

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–400
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

pedestrian alert speaker bspeaker wiringpedestrian alert control module

Related codes

B0122

References: static.nhtsa.gov, eur-lex.europa.eu, static.nhtsa.gov.