Code
C1245
ALFA ROMEO
C — Chassis
Speed signal error
Views:
UK: 21
EN: 24
RU: 19
AI status
Completed
Completed
100%
Causes
- Faulty wheel speed sensor or vehicle speed sensor (VSS)
- Damaged reluctor/tone ring on wheel/hub
- Broken, corroded or disconnected wiring/connectors between sensor and control unit
- Poor ground or low battery/incorrect supply voltage to sensor/module
- Intermittent or failed ABS/ESP control module
- Faulty instrument cluster or multiplex communication fault
Symptoms
- ABS and/or ESC/TC warning lamp illuminated
- Reduced or disabled traction/stability control and cruise control
- Speedometer reading incorrect or erratic
- Intermittent ABS operation or loss of ABS function
- Possible limp-home behaviour from related control systems
What to check
- Use a diagnostic scan tool: read freeze frame, fault details and live data for vehicle speed and individual wheel speeds
- Verify presence/consistency of speed signal(s) while spinning each wheel (lifted) or during low-speed road test
- Visually inspect wheel hub, tone ring and sensor for damage, contamination or missing teeth
- Check connectors and wiring for corrosion, breaks or rubbing points; perform wiggle test while monitoring live data
- Measure sensor supply/reference voltage and ground at the connector with ignition on
- Measure sensor output at connector and at the ECU/ABS module harness to isolate wiring vs sensor
Signal parameters
- Hall-effect/magnetoresistive sensors: digital square-wave pulses referenced to 5 V (or vehicle reference); switching between ~0 V and ~5 V; frequency proportional to wheel speed
- Variable-reluctance (VR) sensors: AC sine-like waveform; amplitude rises with speed (typically a few hundred millivolts to several volts AC depending on speed)
- Pulse frequency should increase smoothly and proportionally with wheel/vehicle speed; all wheel speed sensors should show consistent readings for same-speed rotation
- Open-circuit resistance for passive VR sensors typically measured in ohms (consult vehicle-specific data); short to ground or supply indicates a wiring fault
Diagnostic algorithm
- Connect a capable scan tool and read all stored/active codes and freeze frame. Note which modules report the speed signal fault.
- Check live data: compare vehicle speed and each wheel speed at rest and while rotating wheels (lifted) or during a slow drive. Identify which sensor(s) disagree or are missing.
- Visually inspect suspect sensor(s), tone ring and connector for damage, dirt, loose mounting or missing teeth.
- Perform a wiggle test on wiring while monitoring live data to locate intermittent open/short conditions.
- Measure sensor reference supply and ground at the sensor connector with ignition on. Verify proper voltage and good ground.
- Measure sensor output at the sensor connector while spinning the wheel (multimeter AC for VR; oscilloscope preferred to view waveform). Compare reading at ABS module connector to confirm wiring integrity.
- If sensor signal is absent or implausible at connector but present at module, inspect/repair wiring between sensor and module; if absent at both, replace sensor.
- Inspect tone ring for damage or play in hub bearing that could affect signal. Repair or replace as required.
- After repairs, clear codes and perform a road test to confirm correct speed signals, stable wheel-speed readings and that warning lights do not return.
- If all sensors and wiring check good but error persists, consider ABS/ESP module diagnostic, module ground/power checks or module replacement/updating per manufacturer guidance.
Likely causes
- Contaminated, damaged or disconnected wheel speed sensor
- Damaged/missing teeth on reluctor/tone ring
- Wiring harness damage at wheel (pinch point, corroded connector)
- Failed sensor connector or poor ground at sensor/module
Fault status
Status
ABS/ESP module detects missing or implausible vehicle speed signal; related systems (ABS, ESC, cruise, speedometer) may be degraded or disabled.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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Code
C1245
FIAT
C — Chassis
Speed signal error
Views:
UK: 15
EN: 20
RU: 16
AI status
Completed
Completed
100%
Causes
- Faulty wheel speed sensor or vehicle speed sensor (VSS)
- Damaged reluctor/tone ring on wheel/hub
- Broken, corroded or disconnected wiring/connectors between sensor and control unit
- Poor ground or low battery/incorrect supply voltage to sensor/module
- Intermittent or failed ABS/ESP control module
- Faulty instrument cluster or multiplex communication fault
Symptoms
- ABS and/or ESC/TC warning lamp illuminated
- Reduced or disabled traction/stability control and cruise control
- Speedometer reading incorrect or erratic
- Intermittent ABS operation or loss of ABS function
- Possible limp-home behaviour from related control systems
What to check
- Use a diagnostic scan tool: read freeze frame, fault details and live data for vehicle speed and individual wheel speeds
- Verify presence/consistency of speed signal(s) while spinning each wheel (lifted) or during low-speed road test
- Visually inspect wheel hub, tone ring and sensor for damage, contamination or missing teeth
- Check connectors and wiring for corrosion, breaks or rubbing points; perform wiggle test while monitoring live data
- Measure sensor supply/reference voltage and ground at the connector with ignition on
- Measure sensor output at connector and at the ECU/ABS module harness to isolate wiring vs sensor
Signal parameters
- Hall-effect/magnetoresistive sensors: digital square-wave pulses referenced to 5 V (or vehicle reference); switching between ~0 V and ~5 V; frequency proportional to wheel speed
- Variable-reluctance (VR) sensors: AC sine-like waveform; amplitude rises with speed (typically a few hundred millivolts to several volts AC depending on speed)
- Pulse frequency should increase smoothly and proportionally with wheel/vehicle speed; all wheel speed sensors should show consistent readings for same-speed rotation
- Open-circuit resistance for passive VR sensors typically measured in ohms (consult vehicle-specific data); short to ground or supply indicates a wiring fault
Diagnostic algorithm
- Connect a capable scan tool and read all stored/active codes and freeze frame. Note which modules report the speed signal fault.
- Check live data: compare vehicle speed and each wheel speed at rest and while rotating wheels (lifted) or during a slow drive. Identify which sensor(s) disagree or are missing.
- Visually inspect suspect sensor(s), tone ring and connector for damage, dirt, loose mounting or missing teeth.
- Perform a wiggle test on wiring while monitoring live data to locate intermittent open/short conditions.
- Measure sensor reference supply and ground at the sensor connector with ignition on. Verify proper voltage and good ground.
- Measure sensor output at the sensor connector while spinning the wheel (multimeter AC for VR; oscilloscope preferred to view waveform). Compare reading at ABS module connector to confirm wiring integrity.
- If sensor signal is absent or implausible at connector but present at module, inspect/repair wiring between sensor and module; if absent at both, replace sensor.
- Inspect tone ring for damage or play in hub bearing that could affect signal. Repair or replace as required.
- After repairs, clear codes and perform a road test to confirm correct speed signals, stable wheel-speed readings and that warning lights do not return.
- If all sensors and wiring check good but error persists, consider ABS/ESP module diagnostic, module ground/power checks or module replacement/updating per manufacturer guidance.
Likely causes
- Contaminated, damaged or disconnected wheel speed sensor
- Damaged/missing teeth on reluctor/tone ring
- Wiring harness damage at wheel (pinch point, corroded connector)
- Failed sensor connector or poor ground at sensor/module
Fault status
Status
ABS/ESP module detects missing or implausible vehicle speed signal; related systems (ABS, ESC, cruise, speedometer) may be degraded or disabled.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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Code
C1245
HYUNDAI
C — Chassis
Front Left(FL) Height Sensor Low | Wheel Speed Frequency Error
Views:
UK: 24
EN: 49
RU: 31
AI status
Completed
Completed
100%
Causes
- Faulty wheel speed sensor or vehicle speed sensor (VSS)
- Damaged reluctor/tone ring on wheel/hub
- Broken, corroded or disconnected wiring/connectors between sensor and control unit
- Poor ground or low battery/incorrect supply voltage to sensor/module
- Intermittent or failed ABS/ESP control module
- Faulty instrument cluster or multiplex communication fault
Symptoms
- ABS and/or ESC/TC warning lamp illuminated
- Reduced or disabled traction/stability control and cruise control
- Speedometer reading incorrect or erratic
- Intermittent ABS operation or loss of ABS function
- Possible limp-home behaviour from related control systems
What to check
- Use a diagnostic scan tool: read freeze frame, fault details and live data for vehicle speed and individual wheel speeds
- Verify presence/consistency of speed signal(s) while spinning each wheel (lifted) or during low-speed road test
- Visually inspect wheel hub, tone ring and sensor for damage, contamination or missing teeth
- Check connectors and wiring for corrosion, breaks or rubbing points; perform wiggle test while monitoring live data
- Measure sensor supply/reference voltage and ground at the connector with ignition on
- Measure sensor output at connector and at the ECU/ABS module harness to isolate wiring vs sensor
Signal parameters
- Hall-effect/magnetoresistive sensors: digital square-wave pulses referenced to 5 V (or vehicle reference); switching between ~0 V and ~5 V; frequency proportional to wheel speed
- Variable-reluctance (VR) sensors: AC sine-like waveform; amplitude rises with speed (typically a few hundred millivolts to several volts AC depending on speed)
- Pulse frequency should increase smoothly and proportionally with wheel/vehicle speed; all wheel speed sensors should show consistent readings for same-speed rotation
- Open-circuit resistance for passive VR sensors typically measured in ohms (consult vehicle-specific data); short to ground or supply indicates a wiring fault
Diagnostic algorithm
- Connect a capable scan tool and read all stored/active codes and freeze frame. Note which modules report the speed signal fault.
- Check live data: compare vehicle speed and each wheel speed at rest and while rotating wheels (lifted) or during a slow drive. Identify which sensor(s) disagree or are missing.
- Visually inspect suspect sensor(s), tone ring and connector for damage, dirt, loose mounting or missing teeth.
- Perform a wiggle test on wiring while monitoring live data to locate intermittent open/short conditions.
- Measure sensor reference supply and ground at the sensor connector with ignition on. Verify proper voltage and good ground.
- Measure sensor output at the sensor connector while spinning the wheel (multimeter AC for VR; oscilloscope preferred to view waveform). Compare reading at ABS module connector to confirm wiring integrity.
- If sensor signal is absent or implausible at connector but present at module, inspect/repair wiring between sensor and module; if absent at both, replace sensor.
- Inspect tone ring for damage or play in hub bearing that could affect signal. Repair or replace as required.
- After repairs, clear codes and perform a road test to confirm correct speed signals, stable wheel-speed readings and that warning lights do not return.
- If all sensors and wiring check good but error persists, consider ABS/ESP module diagnostic, module ground/power checks or module replacement/updating per manufacturer guidance.
Likely causes
- Contaminated, damaged or disconnected wheel speed sensor
- Damaged/missing teeth on reluctor/tone ring
- Wiring harness damage at wheel (pinch point, corroded connector)
- Failed sensor connector or poor ground at sensor/module
Fault status
Status
ABS/ESP module detects missing or implausible vehicle speed signal; related systems (ABS, ESC, cruise, speedometer) may be degraded or disabled.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Repair manuals
Manual library for HYUNDAI
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Code
C1245
Other
C — Chassis
ABS Outlet Valve Coil LR Circuit Short To Ground
Views:
UK: 21
EN: 27
RU: 29
AI status
Completed
Completed
100%
Causes
- Faulty wheel speed sensor or vehicle speed sensor (VSS)
- Damaged reluctor/tone ring on wheel/hub
- Broken, corroded or disconnected wiring/connectors between sensor and control unit
- Poor ground or low battery/incorrect supply voltage to sensor/module
- Intermittent or failed ABS/ESP control module
- Faulty instrument cluster or multiplex communication fault
Symptoms
- ABS and/or ESC/TC warning lamp illuminated
- Reduced or disabled traction/stability control and cruise control
- Speedometer reading incorrect or erratic
- Intermittent ABS operation or loss of ABS function
- Possible limp-home behaviour from related control systems
What to check
- Use a diagnostic scan tool: read freeze frame, fault details and live data for vehicle speed and individual wheel speeds
- Verify presence/consistency of speed signal(s) while spinning each wheel (lifted) or during low-speed road test
- Visually inspect wheel hub, tone ring and sensor for damage, contamination or missing teeth
- Check connectors and wiring for corrosion, breaks or rubbing points; perform wiggle test while monitoring live data
- Measure sensor supply/reference voltage and ground at the connector with ignition on
- Measure sensor output at connector and at the ECU/ABS module harness to isolate wiring vs sensor
Signal parameters
- Hall-effect/magnetoresistive sensors: digital square-wave pulses referenced to 5 V (or vehicle reference); switching between ~0 V and ~5 V; frequency proportional to wheel speed
- Variable-reluctance (VR) sensors: AC sine-like waveform; amplitude rises with speed (typically a few hundred millivolts to several volts AC depending on speed)
- Pulse frequency should increase smoothly and proportionally with wheel/vehicle speed; all wheel speed sensors should show consistent readings for same-speed rotation
- Open-circuit resistance for passive VR sensors typically measured in ohms (consult vehicle-specific data); short to ground or supply indicates a wiring fault
Diagnostic algorithm
- Connect a capable scan tool and read all stored/active codes and freeze frame. Note which modules report the speed signal fault.
- Check live data: compare vehicle speed and each wheel speed at rest and while rotating wheels (lifted) or during a slow drive. Identify which sensor(s) disagree or are missing.
- Visually inspect suspect sensor(s), tone ring and connector for damage, dirt, loose mounting or missing teeth.
- Perform a wiggle test on wiring while monitoring live data to locate intermittent open/short conditions.
- Measure sensor reference supply and ground at the sensor connector with ignition on. Verify proper voltage and good ground.
- Measure sensor output at the sensor connector while spinning the wheel (multimeter AC for VR; oscilloscope preferred to view waveform). Compare reading at ABS module connector to confirm wiring integrity.
- If sensor signal is absent or implausible at connector but present at module, inspect/repair wiring between sensor and module; if absent at both, replace sensor.
- Inspect tone ring for damage or play in hub bearing that could affect signal. Repair or replace as required.
- After repairs, clear codes and perform a road test to confirm correct speed signals, stable wheel-speed readings and that warning lights do not return.
- If all sensors and wiring check good but error persists, consider ABS/ESP module diagnostic, module ground/power checks or module replacement/updating per manufacturer guidance.
Likely causes
- Contaminated, damaged or disconnected wheel speed sensor
- Damaged/missing teeth on reluctor/tone ring
- Wiring harness damage at wheel (pinch point, corroded connector)
- Failed sensor connector or poor ground at sensor/module
Fault status
Status
ABS/ESP module detects missing or implausible vehicle speed signal; related systems (ABS, ESC, cruise, speedometer) may be degraded or disabled.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Repair manuals
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