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Home / DTC / B1A04 — Speaker 4 circuit

B1A04 — Speaker 4 circuit

Detailed page for trouble code B1A04.

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22,491specific
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Code

B1A04

LAND ROVER B — Body

Speaker 4 circuit

Brand: LAND ROVER
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted speaker wiring (broken conductor, pinched harness)
  • Failed speaker (shorted voice coil or open windings)
  • Faulty audio amplifier/module output stage
  • Corroded/damaged connector or poor pin contact
  • Blown fuse or failed power/ground to amplifier
  • Water ingress or physical damage to speaker or harness

Symptoms

  • No sound (mute) or reduced level from speaker 4
  • Distorted or intermittent audio from that speaker
  • Imbalance in audio staging (missing channel)
  • DTC B1A04 present in audio module / stored in vehicle fault memory
  • Possible audible buzzing or clipping from affected speaker area

What to check

  • Read and record all audio-related DTCs and freeze frame data with a compatible scan tool
  • Visually inspect speaker 4, its connector, and harness for damage, corrosion or water ingress
  • Check related fuses and amplifier power/ground circuits for presence and continuity
  • Measure DC resistance of speaker 4 at the speaker connector with the speaker disconnected from amplifier
  • Command the speaker output using the diagnostic tool’s speaker test function if available
  • Wiggle the harness and connectors while listening/monitoring for intermittent behavior

Signal parameters

  • Speaker DC resistance (typical): ~2–8 ohms (vehicle-specific — consult spec)
  • Amplifier supply voltage: ~12 V battery at fuse/power input
  • Amplifier ground continuity: close to 0 ohms to chassis ground
  • Speaker output: low-voltage AC/audio or PWM drive (varies with amplifier design)
  • Idle DC offset: may be present on outputs for bridged amplifiers — reference manufacturer data before probing

Diagnostic algorithm

  1. Connect a diagnostic scanner, read and record B1A04 and any related codes; note freeze frame and history.
  2. Locate speaker 4 (consult vehicle speaker numbering) and inspect speaker, grille and nearby wiring for water damage or physical faults.
  3. Visually inspect connectors at speaker and amplifier/head unit; unplug and check pins for corrosion, bent pins or loose terminals.
  4. Check fuses/power: verify the audio amplifier’s supply fuse(s) and power/ground circuits have correct voltage and good ground.
  5. With audio system OFF, measure speaker DC resistance at the speaker connector with speaker disconnected from amplifier; compare to specification and another channel.
  6. Use the diagnostic tool to command a test tone to speaker 4 while probing at the amplifier output and/or speaker connector; observe waveform (oscilloscope preferred) for clipping, DC offset or absence of signal.
  7. If no output at amplifier but power and ground OK, suspect amplifier/module failure. If output present at amp but not at speaker, inspect/repair harness between amp and speaker; check for opens or shorts.
  8. Swap speaker 4 with a known-good speaker on another channel (if wiring identical) to determine if fault follows speaker or stays with channel.
  9. Repair or replace damaged wiring, connector or speaker as indicated. If amplifier is suspected, confirm with bench or module-level testing per manufacturer procedures before replacement.
  10. After repair, clear codes and perform functional test and road/bench verification; ensure code does not return.

Likely causes

  • Speaker 4 itself is open or low impedance (damaged cone/voice coil)
  • Wire chafed and shorting to chassis/ground or to 12V supply
  • Connector pins corroded or pushed out at speaker or amplifier
  • Internal amplifier output transistor/bridge failure
  • Fuse or amplifier power/ground missing causing abnormal output

Fault status

⚠️ Status
Speaker 4 circuit fault detected (open/short/abnormal signal). Fault stored by audio module.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

B1A00 B1A01 B1A02 B1A03 B1A05 B1A06
320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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Code

B1A04

MITSUBISHI B — Body

Keyless/KOS key 5 internal error

Brand: MITSUBISHI
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted speaker wiring (broken conductor, pinched harness)
  • Failed speaker (shorted voice coil or open windings)
  • Faulty audio amplifier/module output stage
  • Corroded/damaged connector or poor pin contact
  • Blown fuse or failed power/ground to amplifier
  • Water ingress or physical damage to speaker or harness

Symptoms

  • No sound (mute) or reduced level from speaker 4
  • Distorted or intermittent audio from that speaker
  • Imbalance in audio staging (missing channel)
  • DTC B1A04 present in audio module / stored in vehicle fault memory
  • Possible audible buzzing or clipping from affected speaker area

What to check

  • Read and record all audio-related DTCs and freeze frame data with a compatible scan tool
  • Visually inspect speaker 4, its connector, and harness for damage, corrosion or water ingress
  • Check related fuses and amplifier power/ground circuits for presence and continuity
  • Measure DC resistance of speaker 4 at the speaker connector with the speaker disconnected from amplifier
  • Command the speaker output using the diagnostic tool’s speaker test function if available
  • Wiggle the harness and connectors while listening/monitoring for intermittent behavior

Signal parameters

  • Speaker DC resistance (typical): ~2–8 ohms (vehicle-specific — consult spec)
  • Amplifier supply voltage: ~12 V battery at fuse/power input
  • Amplifier ground continuity: close to 0 ohms to chassis ground
  • Speaker output: low-voltage AC/audio or PWM drive (varies with amplifier design)
  • Idle DC offset: may be present on outputs for bridged amplifiers — reference manufacturer data before probing

Diagnostic algorithm

  1. Connect a diagnostic scanner, read and record B1A04 and any related codes; note freeze frame and history.
  2. Locate speaker 4 (consult vehicle speaker numbering) and inspect speaker, grille and nearby wiring for water damage or physical faults.
  3. Visually inspect connectors at speaker and amplifier/head unit; unplug and check pins for corrosion, bent pins or loose terminals.
  4. Check fuses/power: verify the audio amplifier’s supply fuse(s) and power/ground circuits have correct voltage and good ground.
  5. With audio system OFF, measure speaker DC resistance at the speaker connector with speaker disconnected from amplifier; compare to specification and another channel.
  6. Use the diagnostic tool to command a test tone to speaker 4 while probing at the amplifier output and/or speaker connector; observe waveform (oscilloscope preferred) for clipping, DC offset or absence of signal.
  7. If no output at amplifier but power and ground OK, suspect amplifier/module failure. If output present at amp but not at speaker, inspect/repair harness between amp and speaker; check for opens or shorts.
  8. Swap speaker 4 with a known-good speaker on another channel (if wiring identical) to determine if fault follows speaker or stays with channel.
  9. Repair or replace damaged wiring, connector or speaker as indicated. If amplifier is suspected, confirm with bench or module-level testing per manufacturer procedures before replacement.
  10. After repair, clear codes and perform functional test and road/bench verification; ensure code does not return.

Likely causes

  • Speaker 4 itself is open or low impedance (damaged cone/voice coil)
  • Wire chafed and shorting to chassis/ground or to 12V supply
  • Connector pins corroded or pushed out at speaker or amplifier
  • Internal amplifier output transistor/bridge failure
  • Fuse or amplifier power/ground missing causing abnormal output

Fault status

⚠️ Status
Speaker 4 circuit fault detected (open/short/abnormal signal). Fault stored by audio module.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

B1A00 B1A01 B1A02 B1A03 B1A05 B1A06
406

Browse 406 MITSUBISHI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MITSUBISHI

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

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