P0720 — Output Speed Sensor Circuit Malfunction

P0720 means the output shaft speed signal is missing or implausible. The transmission can't calculate gear ratio correctly, so it defaults to a safe fixed gear.

Cost range: $150–$900. Severity: high. Safe to drive? Short distances only. Shift quality will be poor and the transmission may stay in limp mode.

Most common causes of P0720

  1. Failed output speed sensor — Common wear item past 100k miles. ($150–$500)
  2. Damaged wiring to the sensor — Under-vehicle exposure to heat and debris. ($100–$350)
  3. Damaged reluctor/tone ring — Requires transmission disassembly. ($800–$2,000)
  4. Low transmission fluid — Rule out before condemning parts. ($100–$350)

Symptoms drivers report with P0720