Output Speed Sensor Circuit Range/Performance
What does P0721 mean?
The P0721 code means the vehicle's onboard diagnostic system has detected: Output Speed Sensor Circuit Range/Performance. This is a critical severity code.
Common Symptoms
- Check Engine Light illuminated
- Speedometer reads incorrectly
- Harsh or delayed shifting
- Transmission slipping
Probable Causes (Ranked by Likelihood)
- Faulty output speed sensor Very High
- Damaged output speed sensor reluctor ring High
- Contaminated fluid with metal debris near sensor Moderate
- TCM output speed circuit fault Low
Step-by-Step Diagnostic Procedure
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Monitor output speed sensor on a scan tool while driving -- should increase smoothly with vehicle speed
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Compare output speed reading to GPS speed for accuracy
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Check transmission fluid for metal particles
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Inspect sensor connector and wiring for damage
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Replace the output speed sensor if readings are erratic
Frequently Asked Questions
Can I drive with code P0721?
Drive short distances only. Output Speed Sensor Circuit Range/Performance can cause unsafe or unpredictable transmission behavior.
What causes P0721?
The most common cause is a faulty sensor or wiring issue. Faulty output speed sensor is the most likely cause.
Is P0721 expensive to fix?
Typical repair costs range from $100 - $350 (parts and labor). Sensor replacement is the most common fix.