Code
C951
PEUGEOT
C — Chassis
Fault on the left-hand rear audio output: Open circuit
AI status
Completed
Completed
100%
Causes
- Broken or open speaker voice coil (speaker internally open)
- Disconnected or damaged speaker connector
- Wiring harness open or chafed (broken conductor)
- Corroded connector or poor pin contact
- Faulty amplifier / amplifier output stage
- Blown fuse or loss of amplifier supply/ground
Symptoms
- No sound from left rear speaker
- Strong left/right imbalance in rear channels
- Infotainment message or fault entry indicating left rear speaker fault
- Intermittent or cut-in audio from left rear (when wiring moves)
- Distorted or very low-level sound if partial connection exists
What to check
- Read stored faults from infotainment/amplifier and note freeze/frame data
- Visually inspect left rear speaker, connector and wiring for damage or corrosion
- Check relevant fuses and amplifier power/ground connections
- Measure speaker DC resistance at the speaker (with harness disconnected)
- Check continuity from amplifier output pin to speaker connector pin
- Swap left rear speaker with a known good speaker or swap channels if possible
Signal parameters
- Expected speaker impedance: typically 2–8 ohms (check vehicle specification)
- Open-circuit result: infinite/OL on ohmmeter between speaker terminals
- Amplifier output AC when playing tone: measurable sine/square waveform (mV–V range) on good channel
- Amplifier output DC offset: close to 0 V (no large DC voltage present)
- Supply voltage to amplifier: approx. battery voltage (~12 V) on power input pins
- Ground continuity: low resistance to chassis ground (
Diagnostic algorithm
- Verify the vehicle and module: confirm C951 is for left rear audio output on this model. Record other related codes.
- Visual inspection: check the left rear speaker, grille, connector, and wiring for obvious damage, water ingress, or corrosion.
- Check fuses and power: verify amplifier/head unit supply fuses and measure 12 V at amplifier power input and good ground.
- Test speaker resistance: disconnect the speaker harness at the speaker and measure DC resistance across speaker terminals. A reading of OL indicates an open speaker.
- Continuity check: with ignition off, measure continuity between the amplifier output pin (consult wiring diagram) and the speaker connector pin. OL indicates open wiring.
- Wiggle/inspect connectors: with connectors mated, gently flex wiring and connectors while playing a test tone to find intermittent connections.
- Functional swap: if possible, connect a known-good speaker to the left rear wiring or swap left/right rear speakers to see if the fault follows the speaker.
- Amplifier output test: if wiring and speaker are good, check amplifier output with an oscilloscope or AC voltmeter while playing a tone. No output suggests amplifier failure.
- Check grounds and supply under load: verify ground and supply while operating to rule out loss under load.
- Repair and verify: repair or replace the defective component (speaker, wiring, connector, amplifier, fuse). Clear codes and confirm no reoccurrence during test drive and prolonged audio playback.
Likely causes
- Open speaker (voice coil failure)
- Open or disconnected speaker wiring / connector at left rear
- Corroded or pushed-out pin at amplifier or speaker connector
- Faulty amplifier channel (output transistor open)
- Missing amplifier supply or ground due to blown fuse or damaged cable
Fault status
Status
Open circuit detected on left rear audio output — no speaker load present or connection lost.
Repair difficulty: Medium
Diagnostic time: 0.5 - 1.5 hours
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email