Code
C0081
Generic
C — Chassis
ABS Malfunction Indicator
Views:
UK: 15
EN: 22
RU: 17
AI status
Completed
Completed
100%
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
- Connect a scan tool and record all ABS, traction and network codes, freeze-frame and live data. Note code return frequency and conditions.
- 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.
- Visually inspect wiring and connectors for corrosion, chafing, rodent damage, loose pins or water intrusion at each wheel sensor and module connector.
- 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.
- Measure sensor resistance (passive sensors) and compare to specification; if open/short or out of range, replace sensor.
- Inspect tone ring/reluctor for damaged or missing teeth and check air gap; correct alignment or replace damaged components as required.
- 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.
- 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.
- 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
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2
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Code
C0081
HYUNDAI
C — Chassis
ABS Malfunction Indicator (Subfault)
Views:
UK: 10
EN: 18
RU: 13
AI status
Completed
Completed
100%
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
- Connect a scan tool and record all ABS, traction and network codes, freeze-frame and live data. Note code return frequency and conditions.
- 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.
- Visually inspect wiring and connectors for corrosion, chafing, rodent damage, loose pins or water intrusion at each wheel sensor and module connector.
- 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.
- Measure sensor resistance (passive sensors) and compare to specification; if open/short or out of range, replace sensor.
- Inspect tone ring/reluctor for damaged or missing teeth and check air gap; correct alignment or replace damaged components as required.
- 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.
- 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.
- 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
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Code
C0081
LAND ROVER
C — Chassis
ABS malfunction indicator
Views:
UK: 7
EN: 10
RU: 4
AI status
Completed
Completed
100%
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
- Connect a scan tool and record all ABS, traction and network codes, freeze-frame and live data. Note code return frequency and conditions.
- 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.
- Visually inspect wiring and connectors for corrosion, chafing, rodent damage, loose pins or water intrusion at each wheel sensor and module connector.
- 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.
- Measure sensor resistance (passive sensors) and compare to specification; if open/short or out of range, replace sensor.
- Inspect tone ring/reluctor for damaged or missing teeth and check air gap; correct alignment or replace damaged components as required.
- 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.
- 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.
- 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
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
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