Output Speed Sensor Circuit Range/Performance
The P0721 code means the vehicle's onboard diagnostic system has detected: Output Speed Sensor Circuit Range/Performance. This is a critical severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $100 - $350 (parts and labor)
Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.
Basic scanners only read engine codes. This reads transmission, ABS, and airbag too.
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What Are the Symptoms of P0721?
- Check Engine Light illuminated
- Speedometer reads incorrectly
- Harsh or delayed shifting
- Transmission slipping
What Causes P0721? (Most Likely First)
- 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
Can I Still Drive with P0721?
Short distances only. P0721 is rated critical severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
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?
Estimated repair costs range from $100 - $350 (parts and labor). Sensor replacement is the most common fix.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0721?
-
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
-
Inspect sensor connector and wiring for damage
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Replace the output speed sensor if readings are erratic
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Which Vehicles Commonly Get P0721?
- 2003-2015 Dodge Ram 1500
- 2004-2016 Jeep Grand Cherokee
- 2005-2017 Ford Explorer
- 2002-2014 Chevrolet Tahoe
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