Skip to main content

P1921 – Transmission Reverse Light Switch Stuck

Want to confirm the real cause of this fault code?

A high‑quality OBD2 scanner gives you live data, fuel trims, sensor readings and freeze‑frame information — exactly what you need to verify the root cause of this code with confidence.

View Recommended Scanners

Symptoms

  • Reverse lights not working
  • Warning light

Causes

  • Switch stuck
  • Mechanical jam
  • Wiring issue

Diagnosis

  • Test switch
  • Inspect wiring
  • Check linkage

Repair

  • Replace switch
  • Repair wiring
  • Fix linkage
Hit enter to search or ESC to close