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Home / DTC / C0081 — ABS Malfunction Indicator

C0081 — ABS Malfunction Indicator

Detailed page for trouble code C0081.

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C0081

Generic C — Chassis

ABS Malfunction Indicator

Brand: Generic
Type: C — Chassis
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Fault stored in ABS control module memory
  • Intermittent or open/short in wheel speed sensor wiring or connectors
  • Failed wheel speed sensor (active or passive)
  • Damaged tone ring/reluctor or excessive air gap
  • Corroded or blown ABS fuse or faulty relay
  • Poor battery or charging system voltage

Symptoms

  • ABS warning lamp illuminated on dash
  • Traction control or electronic stability light may also be on
  • ABS not engaging during hard braking (no pulsation)
  • Increased stopping distance on slippery surfaces when ABS would normally intervene
  • Intermittent or permanent loss of ABS/ESC functionality
  • Possible stored freeze-frame data or multiple ABS-related fault codes

What to check

  • Use a capable scan tool to read/record all ABS and network fault codes and freeze-frame data
  • Confirm battery voltage is within spec (12.4–14.5 V) with engine off and running
  • Visually inspect ABS fuse(s) and related relay(s); verify continuity and operation
  • Inspect wheel speed sensor connectors/wiring and boots for corrosion, damage, pin push-out or water intrusion
  • Rotate each wheel and observe sensor signal with scan tool or oscilloscope (or measure AC voltage on passive sensors)
  • Measure wheel speed sensor DC resistance (if applicable) and compare to factory spec

Signal parameters

  • Passive (magnetic) wheel speed sensor: DC resistance typically ~800–2000 Ω (varies by vehicle); generates AC voltage when wheel rotates (low speed ~0.1–2 V AC, increases with speed)
  • Active (hall/effect) wheel speed sensor: outputs digital square wave referenced to supply (typically 0–5 V or 0–12 V depending on vehicle); frequency proportional to wheel speed
  • Typical sensor air gap: 0.5–3.0 mm (vehicle-specific)
  • ABS module supply voltage: nominal battery voltage ~12–14.5 V; ground should be near 0 V
  • CAN bus idle voltages: approx. 2.5 V on CAN High and CAN Low; differential voltage near 0 V at idle and toggling during communication (tool required to evaluate)

Diagnostic algorithm

  1. Connect a scan tool and record all ABS, traction and network codes, freeze-frame and live data. Note code return frequency and conditions.
  2. Verify basic electrical: battery state, inspect ABS fuse(s) and relay(s), check ABS module power and ground circuits for proper voltage and resistance to chassis ground.
  3. Visually inspect wiring and connectors for corrosion, chafing, rodent damage, loose pins or water intrusion at each wheel sensor and module connector.
  4. With vehicle safely lifted and wheels off the ground, rotate each wheel and observe wheel speed sensor readings on the scan tool or use an oscilloscope to check waveform quality; compare channels for differences.
  5. Measure sensor resistance (passive sensors) and compare to specification; if open/short or out of range, replace sensor.
  6. Inspect tone ring/reluctor for damaged or missing teeth and check air gap; correct alignment or replace damaged components as required.
  7. If one wheel channel is faulty, repair that sensor/wiring/tone ring then clear codes and retest. If multiple channels or network errors exist, check CAN bus integrity and module communication.
  8. If power, ground, wiring and sensors are good but the ABS module remains faulted, consider bench testing or replacement of the ABS control module as per manufacturer procedures. Follow manufacturer programming/relearning after module replacement.
  9. After repairs, clear codes and perform a controlled road test with scan tool to confirm ABS system returns to normal and no codes reappear.

Likely causes

  • Contaminated, broken, or disconnected wheel speed sensor wiring at one wheel
  • Failed wheel speed sensor at one wheel
  • Corroded ABS module power/ground or blown ABS fuse
  • Damaged or missing tone ring teeth at a wheel hub or hub bearing failure affecting sensor signal
  • Intermittent module communication or internal ABS module failure

Fault status

⚠️ Status
ABS warning lamp illuminated; ABS control module has logged a malfunction. ABS/traction control may be disabled or limited until the fault is resolved.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.5-3.0 hours

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Code

C0081

HYUNDAI C — Chassis

ABS Malfunction Indicator (Subfault)

Brand: HYUNDAI
Type: C — Chassis
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Fault stored in ABS control module memory
  • Intermittent or open/short in wheel speed sensor wiring or connectors
  • Failed wheel speed sensor (active or passive)
  • Damaged tone ring/reluctor or excessive air gap
  • Corroded or blown ABS fuse or faulty relay
  • Poor battery or charging system voltage

Symptoms

  • ABS warning lamp illuminated on dash
  • Traction control or electronic stability light may also be on
  • ABS not engaging during hard braking (no pulsation)
  • Increased stopping distance on slippery surfaces when ABS would normally intervene
  • Intermittent or permanent loss of ABS/ESC functionality
  • Possible stored freeze-frame data or multiple ABS-related fault codes

What to check

  • Use a capable scan tool to read/record all ABS and network fault codes and freeze-frame data
  • Confirm battery voltage is within spec (12.4–14.5 V) with engine off and running
  • Visually inspect ABS fuse(s) and related relay(s); verify continuity and operation
  • Inspect wheel speed sensor connectors/wiring and boots for corrosion, damage, pin push-out or water intrusion
  • Rotate each wheel and observe sensor signal with scan tool or oscilloscope (or measure AC voltage on passive sensors)
  • Measure wheel speed sensor DC resistance (if applicable) and compare to factory spec

Signal parameters

  • Passive (magnetic) wheel speed sensor: DC resistance typically ~800–2000 Ω (varies by vehicle); generates AC voltage when wheel rotates (low speed ~0.1–2 V AC, increases with speed)
  • Active (hall/effect) wheel speed sensor: outputs digital square wave referenced to supply (typically 0–5 V or 0–12 V depending on vehicle); frequency proportional to wheel speed
  • Typical sensor air gap: 0.5–3.0 mm (vehicle-specific)
  • ABS module supply voltage: nominal battery voltage ~12–14.5 V; ground should be near 0 V
  • CAN bus idle voltages: approx. 2.5 V on CAN High and CAN Low; differential voltage near 0 V at idle and toggling during communication (tool required to evaluate)

Diagnostic algorithm

  1. Connect a scan tool and record all ABS, traction and network codes, freeze-frame and live data. Note code return frequency and conditions.
  2. Verify basic electrical: battery state, inspect ABS fuse(s) and relay(s), check ABS module power and ground circuits for proper voltage and resistance to chassis ground.
  3. Visually inspect wiring and connectors for corrosion, chafing, rodent damage, loose pins or water intrusion at each wheel sensor and module connector.
  4. With vehicle safely lifted and wheels off the ground, rotate each wheel and observe wheel speed sensor readings on the scan tool or use an oscilloscope to check waveform quality; compare channels for differences.
  5. Measure sensor resistance (passive sensors) and compare to specification; if open/short or out of range, replace sensor.
  6. Inspect tone ring/reluctor for damaged or missing teeth and check air gap; correct alignment or replace damaged components as required.
  7. If one wheel channel is faulty, repair that sensor/wiring/tone ring then clear codes and retest. If multiple channels or network errors exist, check CAN bus integrity and module communication.
  8. If power, ground, wiring and sensors are good but the ABS module remains faulted, consider bench testing or replacement of the ABS control module as per manufacturer procedures. Follow manufacturer programming/relearning after module replacement.
  9. After repairs, clear codes and perform a controlled road test with scan tool to confirm ABS system returns to normal and no codes reappear.

Likely causes

  • Contaminated, broken, or disconnected wheel speed sensor wiring at one wheel
  • Failed wheel speed sensor at one wheel
  • Corroded ABS module power/ground or blown ABS fuse
  • Damaged or missing tone ring teeth at a wheel hub or hub bearing failure affecting sensor signal
  • Intermittent module communication or internal ABS module failure

Fault status

⚠️ Status
ABS warning lamp illuminated; ABS control module has logged a malfunction. ABS/traction control may be disabled or limited until the fault is resolved.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.5-3.0 hours

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C0035 C0040 C0050 C0060 C0080 C0265
371

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HYUNDAI

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Code

C0081

LAND ROVER C — Chassis

ABS malfunction indicator

Brand: LAND ROVER
Type: C — Chassis
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Fault stored in ABS control module memory
  • Intermittent or open/short in wheel speed sensor wiring or connectors
  • Failed wheel speed sensor (active or passive)
  • Damaged tone ring/reluctor or excessive air gap
  • Corroded or blown ABS fuse or faulty relay
  • Poor battery or charging system voltage

Symptoms

  • ABS warning lamp illuminated on dash
  • Traction control or electronic stability light may also be on
  • ABS not engaging during hard braking (no pulsation)
  • Increased stopping distance on slippery surfaces when ABS would normally intervene
  • Intermittent or permanent loss of ABS/ESC functionality
  • Possible stored freeze-frame data or multiple ABS-related fault codes

What to check

  • Use a capable scan tool to read/record all ABS and network fault codes and freeze-frame data
  • Confirm battery voltage is within spec (12.4–14.5 V) with engine off and running
  • Visually inspect ABS fuse(s) and related relay(s); verify continuity and operation
  • Inspect wheel speed sensor connectors/wiring and boots for corrosion, damage, pin push-out or water intrusion
  • Rotate each wheel and observe sensor signal with scan tool or oscilloscope (or measure AC voltage on passive sensors)
  • Measure wheel speed sensor DC resistance (if applicable) and compare to factory spec

Signal parameters

  • Passive (magnetic) wheel speed sensor: DC resistance typically ~800–2000 Ω (varies by vehicle); generates AC voltage when wheel rotates (low speed ~0.1–2 V AC, increases with speed)
  • Active (hall/effect) wheel speed sensor: outputs digital square wave referenced to supply (typically 0–5 V or 0–12 V depending on vehicle); frequency proportional to wheel speed
  • Typical sensor air gap: 0.5–3.0 mm (vehicle-specific)
  • ABS module supply voltage: nominal battery voltage ~12–14.5 V; ground should be near 0 V
  • CAN bus idle voltages: approx. 2.5 V on CAN High and CAN Low; differential voltage near 0 V at idle and toggling during communication (tool required to evaluate)

Diagnostic algorithm

  1. Connect a scan tool and record all ABS, traction and network codes, freeze-frame and live data. Note code return frequency and conditions.
  2. Verify basic electrical: battery state, inspect ABS fuse(s) and relay(s), check ABS module power and ground circuits for proper voltage and resistance to chassis ground.
  3. Visually inspect wiring and connectors for corrosion, chafing, rodent damage, loose pins or water intrusion at each wheel sensor and module connector.
  4. With vehicle safely lifted and wheels off the ground, rotate each wheel and observe wheel speed sensor readings on the scan tool or use an oscilloscope to check waveform quality; compare channels for differences.
  5. Measure sensor resistance (passive sensors) and compare to specification; if open/short or out of range, replace sensor.
  6. Inspect tone ring/reluctor for damaged or missing teeth and check air gap; correct alignment or replace damaged components as required.
  7. If one wheel channel is faulty, repair that sensor/wiring/tone ring then clear codes and retest. If multiple channels or network errors exist, check CAN bus integrity and module communication.
  8. If power, ground, wiring and sensors are good but the ABS module remains faulted, consider bench testing or replacement of the ABS control module as per manufacturer procedures. Follow manufacturer programming/relearning after module replacement.
  9. After repairs, clear codes and perform a controlled road test with scan tool to confirm ABS system returns to normal and no codes reappear.

Likely causes

  • Contaminated, broken, or disconnected wheel speed sensor wiring at one wheel
  • Failed wheel speed sensor at one wheel
  • Corroded ABS module power/ground or blown ABS fuse
  • Damaged or missing tone ring teeth at a wheel hub or hub bearing failure affecting sensor signal
  • Intermittent module communication or internal ABS module failure

Fault status

⚠️ Status
ABS warning lamp illuminated; ABS control module has logged a malfunction. ABS/traction control may be disabled or limited until the fault is resolved.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.5-3.0 hours

Similar codes

C0035 C0040 C0050 C0060 C0080 C0265
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

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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