B0122 is a body control module code indicating a malfunction in the pedestrian alert speaker circuit (also called Vehicle Sound for Pedestrians or VSP). This speaker is required on electric and hybrid vehicles to generate audible warning sounds at low speeds for pedestrian safety. The code is set when the module detects an open, short, or implausible signal in the speaker circuit.
The speaker itself has failed due to age, moisture ingress, or physical damage, creating an open or shorted circuit.
Wiring harness to the speaker is damaged, corroded, or connector pins are broken/loose, causing intermittent or open circuits.
A fuse related to the pedestrian alert system has blown, or there is a power distribution issue preventing the circuit from functioning.
The body control module or hybrid vehicle control unit that commands the pedestrian alert system has failed or lost calibration.
The vehicle's control software may have a glitch or require an update affecting the pedestrian alert system operation.
The main engine/powertrain computer is almost never the cause of B0122; replacing it for this code is almost always unnecessary and costly.
The vehicle will still drive, but you may be in violation of local regulations requiring pedestrian warning sounds. Some vehicles may also enter a reduced-power or low-speed mode as a safety precaution.
Legally, no. Disabling or removing the pedestrian alert system is prohibited on most electric and hybrid vehicles, as it violates safety regulations designed to protect blind and visually impaired pedestrians.
No, replacing the powertrain control module (PCM/ECM) for B0122 is almost never correct. This code almost always points to the speaker itself, its wiring, or a related fuse. PCM replacement for this code is a common misdiagnosis that results in unnecessary expense.
OEM pedestrian alert speakers typically cost significantly less than the thousands of dollars sometimes quoted for full system repairs or computer replacements. Exact pricing varies by vehicle make and model.