P0502 – Vehicle Speed Sensor Low Input

Description

The ECM detects a low voltage signal from the vehicle speed sensor.

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Symptoms

  • Speedometer drops to zero
  • Harsh shifting
  • ABS light on

Causes

  • Short to ground
  • Faulty VSS sensor
  • Damaged wiring

Diagnosis

  • Monitor VSS voltage
  • Inspect wiring
  • Check sensor resistance

Repair

  • Repair wiring
  • Replace VSS sensor