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Diagnose/P0721
P0721High SeverityTransmission

Output Speed Sensor Circuit Range/Performance

What This Means

The transmission output speed sensor readings are outside expected range. This sensor measures output shaft speed to determine vehicle speed and control shift points.

Common Symptoms

  • Speedometer not working
  • Harsh or delayed shifts
  • Transmission may not shift
  • ABS/traction lights on

Common Causes

  • Failed output speed sensor
  • Damaged wiring
  • Metallic contamination
  • Damaged tone ring
  • Fluid contamination

Estimated Repair Cost

$150 – $700
Parts and labor (varies by vehicle and location)
Difficulty:Advanced

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For informational purposes only. Diagnostic trouble codes are starting points for diagnosis, not definitive answers. Always consult a certified mechanic for proper diagnosis and repair. Estimated costs vary by vehicle, location, and shop rates.