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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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
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
Step-by-Step Diagnostic Procedure
-
Monitor output speed sensor on a scan tool while driving -- should increase smoothly with vehicle speed
-
Compare output speed reading to GPS speed for accuracy
-
Check transmission fluid for metal particles
-
Inspect sensor connector and wiring for damage
-
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)
Commonly Affected Vehicles
- 2003-2015 Dodge Ram 1500
- 2004-2016 Jeep Grand Cherokee
- 2005-2017 Ford Explorer
- 2002-2014 Chevrolet Tahoe
Related Codes
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