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C1124 Manufacturer-specific Basic entry

Input shaft speed signal missing/faulted

Updated 2026-10-02 · Chassis (manufacturer-specific)

Severity
Medium
Typical repair cost
60 – 500 EUR
System
Chassis

This is a manufacturer-specific code. Its exact meaning can differ between makes; the definition below follows the most common usage.

What it means

C1124 is defined as "Input shaft speed signal missing/faulted". the chassis control module (ABS/ESP) stores it when the monitored condition for this component or system is outside the limits programmed by the manufacturer.

This entry is compiled automatically from the standard definition and typical diagnostic practice for this type of fault. A detailed, reviewed article is in preparation.

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Symptoms

  • ABS, ESP or traction control warning light
  • Stability and traction systems disabled
  • Possible longer braking distance in emergency stops
  • Speedometer or cruise control affected in some vehicles

Common causes

  1. Input shaft speed signal missing/faulted worn, contaminated or out of calibration
  2. Mechanical problem in the system the sensor measures
  3. Air, vacuum or exhaust leak influencing the reading
  4. Wrong or low-quality replacement part
  5. Wiring resistance causing a small voltage offset

How to diagnose

  1. Compare the live Input shaft speed signal missing/faulted reading with a known-good value or a second sensor at idle and at 2500 rpm
  2. Check for air, vacuum or exhaust leaks that could skew the reading
  3. Inspect the component for contamination and clean it if the design allows
  4. Verify the part number is correct for the engine
  5. Replace the Input shaft speed signal missing/faulted if the reading remains out of specification

Frequently asked questions

Can I keep driving with C1124?

Usually yes for a short time, but expect reduced performance or higher fuel use. Have it diagnosed within a few days.

Will clearing C1124 fix it?

No. Clearing only erases the stored code; it returns as soon as the monitor runs again unless the cause is repaired.

Related codes

C1123C1125C1126

Nearby codes in this group