Code
B0123
Generic
B — Body
Pedestrian Alert Speaker B
Views:
UK: 23
EN: 24
RU: 19
AI status
Completed
Completed
100%
Causes
- Open or short in Pedestrian Alert Speaker B wiring or connector
- Corroded or loose connector pins at the speaker or control module
- Failed pedestrian alert speaker (coil open/short or mechanical failure)
- Blown fuse or failed relay in the audio/auxiliary supply circuit
- Faulty audio amplifier/driver or body control module output stage
- Water intrusion or physical damage to speaker assembly
Symptoms
- No pedestrian alert sound from speaker B (reduced or no volume)
- Distorted or intermittent alert tones from the pedestrian area
- DTC present in scan tool with related audio module warnings
- Possible audible clicking or static from speaker area
- Related features (if multi-speaker) may function but with reduced coverage
What to check
- Scan vehicle with a capable scan tool and confirm B0123 is current or historic; record freeze frame and module data
- Visual inspection of speaker B, connector, and wiring harness for damage, corrosion, or water entry
- Verify related fuses and relays for audio/pedestrian alert circuit
- Check for other related DTCs in body, audio, or network modules
- Attempt to reproduce symptom while monitoring live data and module outputs
- Listen at speaker location while commanding pedestrian alert tone (use scan tool/bi-directional test if available)
Signal parameters
- Expected speaker impedance: typically 4–8 ohms (consult vehicle spec)
- Voltage at speaker connector (no-signal): near 0 V DC or module-specific bias (measure reference to ground)
- Drive signal: audio waveform or PWM from amplifier; amplitude varies with volume command
- Continuity: near 4–8 ohms across speaker terminals (resistance measurement)
- Open-circuit: very high/OL resistance across speaker terminals
- Short to ground/12V: near 0 ohms to ground or battery voltage present on both terminals
Diagnostic algorithm
- Connect a scan tool, confirm B0123 and note freeze-frame/related codes. Clear code and attempt to re-create to confirm persistence.
- Inspect speaker B connector and wiring visually for damage, corrosion, water, pin-back, or loose terminals. Repair any obvious issues and retest.
- Verify fuses and any supply relays for the pedestrian alert/audio circuit. Replace faulty fuses/relays as needed.
- With ignition on (follow manufacturer safety), unplug speaker B connector and measure resistance across speaker leads at the connector. If open or out of spec, suspect speaker failure or open circuit.
- If speaker resistance is normal, backprobe connector at the module end to check for drive signal while commanding an alert tone (use scope or audio probe). Look for expected waveform or PWM. No drive indicates driver/module fault.
- If drive signal is present at module but not at speaker connector, inspect harness for open/short between module and speaker; repair wiring and retest.
Likely causes
- Speaker element failure (open coil or shorted voice coil)
- Disconnected or corroded speaker connector
- Broken wire or pinched harness to speaker B
- Failed amplifier/driver output on body control module
- Blown fuse supplying pedestrian alert audio system
Fault status
Status
B0123 - Pedestrian Alert Speaker B Circuit Fault (open/short/low output).
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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