Code
CF00
CITROEN
C — Chassis
Microphone input fault: Open circuit
AI status
Completed
Completed
100%
Causes
- Broken or disconnected microphone element
- Open or damaged wiring between microphone and control module
- Loose, corroded or pushed-out connector pins
- Failed microphone preamplifier or hands-free control module input stage
- Aftermarket installations or recent repairs with incorrect wiring
Symptoms
- No voice input on phone calls or voice recognition
- Hands-free microphone not detected or mute by system
- Voice commands ignored or poor/no audio level on caller's side
- DTC stored in telephony/audio module memory
- Occasional intermittent operation if wiring is damaged
What to check
- Check for any recent work in roof liner, pillar trim, or steering column that could have disturbed the microphone connector
- Visually inspect microphone, connector and harness for damage, corrosion or disconnection
- With ignition ON, measure for bias voltage at the microphone connector (refer to signal parameters)
- Perform continuity check between microphone connector and module input pin(s)
- Swap in a known-good microphone (or short test plug) to confirm module input
- Scan for other related codes (communication faults, power supply, ground faults)
Signal parameters
- Microphone bias voltage at module input (ignition ON): typically around 2–3 V DC (varies by model). Open circuit = no bias present at microphone pin.
- Microphone impedance: typical electret microphone element ~1–10 kΩ; open circuit will show infinite/very high resistance.
- AC audio level when speaking near microphone: small millivolt AC waveform (tens to hundreds of mV peak-to-peak) present on the signal line when working.
- Connector continuity: expect low ohms between microphone housing ground and module ground; signal line continuity to module pin should be present.
Diagnostic algorithm
- Read and record freeze frame/fault details with a compatible diagnostic tool. Note module that logged CF00 and any related faults.
- Ask operator about recent interior work (headliner, mirror, overhead console) that could have disturbed connectors.
- Visually inspect microphone assembly and its connector for damage, corrosion or a pushed-out terminal.
- With ignition ON (accessory), probe the microphone connector: check for DC bias on the signal pin and ground continuity. If no bias, suspect open wiring or module supply issue.
- If bias present at module side but not at microphone plug, perform continuity check of signal wire between microphone plug and module input. Repair any open circuit.
- If open persists but wiring is intact, remove microphone and bench-test or substitute known-good microphone to confirm microphone failure.
- If microphone and wiring are good but module shows open, inspect module power/ground and CAN/communication lines; replace module only after verifying input stage fault.
- After repair, clear DTCs and verify functionality: perform call/voice recognition test and re-scan to confirm CF00 does not return.
- Safety note: take care removing trim or headliner near airbags and follow manufacturer procedures when accessing roof-mounted components.
Likely causes
- Disconnected/loose microphone connector (common after trim removal)
- Wiring chafed through or broken near hinge points (doors, roof-liner)
- Corrosion in connector causing open circuit
- Failed microphone (internal open element)
- Failed or unpowered audio/telephony module
Fault status
Status
Microphone input — Open circuit detected (no signal or continuity at microphone input).
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
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Code
CF00
DS
C — Chassis
Microphone input fault: Open circuit
AI status
Completed
Completed
100%
Causes
- Broken or disconnected microphone element
- Open or damaged wiring between microphone and control module
- Loose, corroded or pushed-out connector pins
- Failed microphone preamplifier or hands-free control module input stage
- Aftermarket installations or recent repairs with incorrect wiring
Symptoms
- No voice input on phone calls or voice recognition
- Hands-free microphone not detected or mute by system
- Voice commands ignored or poor/no audio level on caller's side
- DTC stored in telephony/audio module memory
- Occasional intermittent operation if wiring is damaged
What to check
- Check for any recent work in roof liner, pillar trim, or steering column that could have disturbed the microphone connector
- Visually inspect microphone, connector and harness for damage, corrosion or disconnection
- With ignition ON, measure for bias voltage at the microphone connector (refer to signal parameters)
- Perform continuity check between microphone connector and module input pin(s)
- Swap in a known-good microphone (or short test plug) to confirm module input
- Scan for other related codes (communication faults, power supply, ground faults)
Signal parameters
- Microphone bias voltage at module input (ignition ON): typically around 2–3 V DC (varies by model). Open circuit = no bias present at microphone pin.
- Microphone impedance: typical electret microphone element ~1–10 kΩ; open circuit will show infinite/very high resistance.
- AC audio level when speaking near microphone: small millivolt AC waveform (tens to hundreds of mV peak-to-peak) present on the signal line when working.
- Connector continuity: expect low ohms between microphone housing ground and module ground; signal line continuity to module pin should be present.
Diagnostic algorithm
- Read and record freeze frame/fault details with a compatible diagnostic tool. Note module that logged CF00 and any related faults.
- Ask operator about recent interior work (headliner, mirror, overhead console) that could have disturbed connectors.
- Visually inspect microphone assembly and its connector for damage, corrosion or a pushed-out terminal.
- With ignition ON (accessory), probe the microphone connector: check for DC bias on the signal pin and ground continuity. If no bias, suspect open wiring or module supply issue.
- If bias present at module side but not at microphone plug, perform continuity check of signal wire between microphone plug and module input. Repair any open circuit.
- If open persists but wiring is intact, remove microphone and bench-test or substitute known-good microphone to confirm microphone failure.
- If microphone and wiring are good but module shows open, inspect module power/ground and CAN/communication lines; replace module only after verifying input stage fault.
- After repair, clear DTCs and verify functionality: perform call/voice recognition test and re-scan to confirm CF00 does not return.
- Safety note: take care removing trim or headliner near airbags and follow manufacturer procedures when accessing roof-mounted components.
Likely causes
- Disconnected/loose microphone connector (common after trim removal)
- Wiring chafed through or broken near hinge points (doors, roof-liner)
- Corrosion in connector causing open circuit
- Failed microphone (internal open element)
- Failed or unpowered audio/telephony module
Fault status
Status
Microphone input — Open circuit detected (no signal or continuity at microphone input).
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
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0
Send to email
Code
CF00
PEUGEOT
C — Chassis
Microphone input fault: Open circuit
AI status
Completed
Completed
100%
Causes
- Broken or disconnected microphone element
- Open or damaged wiring between microphone and control module
- Loose, corroded or pushed-out connector pins
- Failed microphone preamplifier or hands-free control module input stage
- Aftermarket installations or recent repairs with incorrect wiring
Symptoms
- No voice input on phone calls or voice recognition
- Hands-free microphone not detected or mute by system
- Voice commands ignored or poor/no audio level on caller's side
- DTC stored in telephony/audio module memory
- Occasional intermittent operation if wiring is damaged
What to check
- Check for any recent work in roof liner, pillar trim, or steering column that could have disturbed the microphone connector
- Visually inspect microphone, connector and harness for damage, corrosion or disconnection
- With ignition ON, measure for bias voltage at the microphone connector (refer to signal parameters)
- Perform continuity check between microphone connector and module input pin(s)
- Swap in a known-good microphone (or short test plug) to confirm module input
- Scan for other related codes (communication faults, power supply, ground faults)
Signal parameters
- Microphone bias voltage at module input (ignition ON): typically around 2–3 V DC (varies by model). Open circuit = no bias present at microphone pin.
- Microphone impedance: typical electret microphone element ~1–10 kΩ; open circuit will show infinite/very high resistance.
- AC audio level when speaking near microphone: small millivolt AC waveform (tens to hundreds of mV peak-to-peak) present on the signal line when working.
- Connector continuity: expect low ohms between microphone housing ground and module ground; signal line continuity to module pin should be present.
Diagnostic algorithm
- Read and record freeze frame/fault details with a compatible diagnostic tool. Note module that logged CF00 and any related faults.
- Ask operator about recent interior work (headliner, mirror, overhead console) that could have disturbed connectors.
- Visually inspect microphone assembly and its connector for damage, corrosion or a pushed-out terminal.
- With ignition ON (accessory), probe the microphone connector: check for DC bias on the signal pin and ground continuity. If no bias, suspect open wiring or module supply issue.
- If bias present at module side but not at microphone plug, perform continuity check of signal wire between microphone plug and module input. Repair any open circuit.
- If open persists but wiring is intact, remove microphone and bench-test or substitute known-good microphone to confirm microphone failure.
- If microphone and wiring are good but module shows open, inspect module power/ground and CAN/communication lines; replace module only after verifying input stage fault.
- After repair, clear DTCs and verify functionality: perform call/voice recognition test and re-scan to confirm CF00 does not return.
- Safety note: take care removing trim or headliner near airbags and follow manufacturer procedures when accessing roof-mounted components.
Likely causes
- Disconnected/loose microphone connector (common after trim removal)
- Wiring chafed through or broken near hinge points (doors, roof-liner)
- Corrosion in connector causing open circuit
- Failed microphone (internal open element)
- Failed or unpowered audio/telephony module
Fault status
Status
Microphone input — Open circuit detected (no signal or continuity at microphone input).
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
Similar codes
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