B0123: Pedestrian Alert Speaker B

What it means

The control module monitors the electrical circuit for pedestrian alert speaker B. It sets this code when the circuit signal indicates a fault, such as an open or short, or the speaker does not respond as expected during a system check.

At a glance

• Usually lights the airbag (SRS) or body-system warning light

How it works

Pedestrian alert speaker B produces an artificial sound to make some electric and hybrid vehicles easier to hear at low speeds. The control module checks speaker B’s output circuit and response; this code sets when it detects an electrical fault or the speaker does not respond as expected.

Common causes

Most likely first.

1. Failed pedestrian alert speaker
2. Open or shorted speaker wiring
3. Loose or corroded connector
4. Blown fuse or power supply fault
5. Fault in the speaker output circuit

Symptoms

• Warning light or symbol related to the affected system
• Comfort or safety function impaired

How to diagnose it

1. Record freeze-frame data and check for related pedestrian-alert or power-supply codes that may point to a shared fault.
2. At a safe low speed, determine whether the expected alert sound is absent or distorted, noting that speaker B may cover a different channel or condition from speaker A.
3. Inspect speaker B and its connector for impact damage, water entry, corrosion, loose fit, or pushed-back pins.
4. Check the speaker B harness for breaks, chafing, pinching, or damage, and inspect the relevant fuse and supply circuit using the vehicle’s wiring information.
5. Test speaker B and its output circuit for continuity, shorts, and module response according to the manufacturer’s specification.

Common fixes

• Reconnect or clean speaker B’s connector and repair damaged terminals.
• Repair damaged wiring in the speaker B circuit.
• Replace a failed fuse or restore the identified power-supply fault after checking for its cause.
• Replace pedestrian alert speaker B if its circuit tests correctly but it does not produce the commanded sound.
• Repair the speaker output circuit or control module if testing isolates the fault there.

Can I keep driving?

The vehicle may be harder for pedestrians to hear at low speeds, so drive cautiously in shared spaces and do not assume the alert sound is operating. Arrange repair promptly, especially if the vehicle is often driven where people may not see it.