Code
B0122
Generic
B — Body
Pedestrian Alert Speaker A
Views:
UK: 21
EN: 27
RU: 24
AI status
Completed
Completed
100%
Causes
- Open or short in the Pedestrian Alert Speaker A wiring harness
- Poor or corroded connector or pin contact at the speaker or control module
- Failed pedestrian alert speaker (burnt voice coil or mechanical damage)
- Faulty amplifier/AVAS control unit or BCM output driver
- Blown fuse or loss of supply/ground to the speaker circuit
- Water intrusion or physical damage to the speaker or connector
Symptoms
- No pedestrian alert/AVAS sound when system should be active (e.g., low-speed EV/HEV operation)
- Reduced or distorted pedestrian alert sound (low volume, buzz, intermittent)
- DTC present in body/module causing related warnings or disabled AVAS output
- Sound works intermittently or only when pressing on the speaker area (indicates mechanical/wiring fault)
What to check
- Scan vehicle and record B0122 plus any other stored codes and freeze-frame data
- Visually inspect the pedestrian speaker, housing and connector for water, corrosion, physical damage or foreign objects
- Check fuses and power supply circuits related to AVAS/BOSE/Audio/BCM as applicable
- Wiggle-test harness and connectors while listening for changes in sound or checking for code set
- Measure speaker connector voltage (key ON) and ground presence
- Measure speaker DC resistance with connector disconnected (compare to expected spec)
Signal parameters
- Typical speaker DC bias (key ON): ~6–12 V (varies by vehicle)
- Audio overlay: AC audio waveform riding on DC bias; amplitude may be several volts peak-to-peak
- Speaker impedance: commonly 4–8 Ω for small external speakers (check vehicle spec)
- Activation: audio signal present when AVAS/pedestrian alert is commanded (frequency content typically 500–4,000 Hz)
- Expected behavior: clean audio waveform on scope; no constant short to ground or battery
Diagnostic algorithm
- Retrieve and record codes and freeze frame; note vehicle conditions when DTC set. Clear codes and attempt to reproduce with a drive/activation cycle.
- Perform a visual inspection of Pedestrian Alert Speaker A, its mounting, and harness for water, corrosion, damaged insulation, or push-out pins. Repair any obvious damage.
- Check related fuses and supply voltages at the speaker/AVAS module with key ON. Verify a good chassis ground at the speaker mounting point.
- Disconnect speaker connector and measure DC resistance of the speaker. If open or shorted, replace the speaker. Typical values are in the 4–8 Ω range—consult vehicle spec.
- With the AVAS/alert system commanded ON (use diagnostic tool’s actuator if available), probe the speaker harness at the module end with an oscilloscope or voltmeter. Look for an audio waveform or pulsed output. If signal is present but speaker produces no sound, replace the speaker.
- If no signal at the harness, trace wiring back to the AVAS module/BCM: check continuity, shorts to ground/battery, and connector pin integrity. Repair wiring or connector faults.
Likely causes
- Broken or chafed speaker lead (open circuit)
- Short to ground or battery on speaker output
- High-resistance ground or power connection at speaker
- Speaker voice coil open or shorted
- Connector pins pushed out/corroded allowing intermittent contact
- Failed output stage inside AVAS/BCM module
Fault status
Status
Body control detected a fault in the Pedestrian Alert Speaker A circuit — open, short, or speaker malfunction.
Repair difficulty: Medium
Diagnostic time: 0.5–2.0 hours
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