Parts
$20-120
P0720 — Output Speed Sensor Circuit
CAUTIONIs it safe to drive? The output speed sensor is failing — the TCM can't calculate vehicle speed for shifting. Speedometer may be wrong; avoid highway speeds until fixed.
What P0720 means
The output speed sensor tells the TCM how fast the output shaft is turning. This is used to calculate shift points, TCC lockup, and in many cases feeds the speedometer. A failed signal causes poor shift quality and ABS/stability codes may follow.
Most likely causes (in order)
- Failed output speed sensor
- Wiring or connector fault
- Metallic debris on the sensor tip
- Low or contaminated transmission fluid
Symptoms you might notice
- Speedometer errors
- Harsh or missed shifts
- ABS light on some vehicles
- Limp mode
What to check first
Compare the output speed sensor reading on a scan tool against actual vehicle speed. Inspect the sensor tip for metal debris — a sign of internal wear. Check fluid first.
Repair cost & difficulty
Labor
0.5-2 hr
Difficulty
DIY-friendly