B0401moderate severityBody

Speedometer Circuit Malfunction

on 2007 Mercedes-Benz S65 AMG 6.0L V12 BiTurbo M275 ยท RWD

What this code means

The speedometer gauge is not functioning or is displaying incorrect speed readings.

Symptoms

  • Speedometer reads zero while driving
  • Speedometer reads erratically
  • Speedometer needle bouncing
  • Cruise control may not work

Common causes

  • Faulty vehicle speed sensor
  • Instrument cluster stepper motor failure
  • Cluster circuit board fault
  • Speed signal wiring issue

Diagnostic steps

  1. Check speed sensor signal with scan tool
  2. Compare GPS speed to speedometer
  3. Test cluster stepper motor
  4. Check speed sensor wiring
  5. Scan for related speed sensor codes

Repair notes

Replace speed sensor or instrument cluster stepper motor. If cluster board is faulty, replace or repair cluster.

Other Body codes on this vehicle

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