Body, generic

B0122 Pedestrian Alert Speaker A

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0122 flags pedestrian alert speaker A. Hybrid and electric vehicles are almost silent at walking pace, so they have to make an artificial sound. In the US, FMVSS 141 covers such vehicles up to 4,536 kg GVWR and sets minimum sound levels when stationary with propulsion active, in reverse and up to 30 km/h. GM's preliminary information PIC6478 for the 2023 Cadillac Lyriq shows a typical front speaker behind the bumper: it plays from standstill to about 25 mph, can be silenced for diagnosis by pulling fuse F46UA, and its bracket may buzz against the bumper beam. Which speaker is A is not published, and no maker documents B0122. With the speaker dead the car loses its mandatory warning sound but drives normally.

Likely causes

Speaker A failed from water, salt or stone impact at the front end
Open or short in the speaker wiring, often after bumper repairs
Output stage of the sound generator module or its fuse faulty

Symptoms

  • No artificial driving sound at low speed from the affected side
  • Warning message about the pedestrian alert system in the cluster, depending on make
  • Vehicle no longer meets the legal minimum sound; repair promptly

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 aspeaker wiringpedestrian alert control module

Related codes

B0123

References: law.cornell.edu, static.nhtsa.gov.