Seeing a P0720 code on your scanner can be concerning, especially when your vehicle starts shifting erratically or the speedometer stops working. This OBD-II trouble code, known as “Output Speed Sensor Circuit Malfunction”, often signals deeper issues within your car’s transmission system. Whether you’re driving a Ford F-150, Infiniti Q50, or another vehicle with electronic transmission control, understanding this code is crucial for avoiding long-term damage. In this guide, you’ll learn what the P0720 code means, what causes it, how to recognize its symptoms, and—most importantly—how to fix it safely and effectively.
What Is the P0720 Code?
The P0720 code is a diagnostic trouble code (DTC) defined as:
“Output Speed Sensor Circuit Malfunction”
This means the powertrain control module (PCM) is not receiving proper data from the output speed sensor. The sensor is responsible for monitoring the rotational speed of the transmission’s output shaft and comparing it to the input shaft speed to ensure proper gear ratios.
Common Vehicles Affected by P0720
This code is commonly reported in:
- Ford F-150
- Infiniti Q50 / G20
- Nissan Altima / Maxima
- Mazda 3 / 6
- Dodge Ram 1500
- Toyota Corolla (CVT models)
Symptoms of Code P0720
When the P0720 code is triggered, you may notice:
- Check Engine Light is illuminated
- Harsh, delayed, or unpredictable shifting
- Speedometer not working or showing erratic readings
- Transmission slipping or failure to engage certain gears
- Vehicle entering limp mode
- Reduced fuel efficiency
What Causes the P0720 Code?
The most common causes behind the PO720 error code include:
- Faulty Output Speed Sensor
- Damaged, shorted, or corroded wiring/connectors
- Dirty or low transmission fluid
- Failed Powertrain Control Module (PCM) or Transmission Control Module (TCM)
- Internal transmission issues
- Sensor misalignment or contamination by debris
How to Fix Code P0720
Wondering how to fix PO720? Follow these steps:
✅ 1. Scan for Additional Trouble Codes
Use a professional OBD-II scanner to detect all related transmission codes such as P0715, P0730, or P0500.
✅ 2. Inspect the Output Speed Sensor
Check for physical damage, corrosion, or loose connectors. Most output speed sensors are located near the vehicle’s transmission tailshaft.
✅ 3. Check Transmission Fluid Condition
Dirty or low ATF can interfere with sensor readings. Be sure to check your oil and transmission fluid properly.
✅ 4. Examine the Wiring and Connectors
Look for frayed wires, moisture, and corrosion. Use a multimeter to verify voltage and continuity.
✅ 5. Replace the Output Speed Sensor
If the sensor is confirmed faulty, replace it. This is typically a simple and inexpensive fix.
✅ 6. Reprogram or Replace PCM/TCM
In rare cases, the powertrain control module may require software updates or replacement.
Can You Drive with a P0720 Code?
While your vehicle might still run, it’s not safe to drive for long with the PO720 code active. Transmission performance may be impaired, and driving in limp mode can cause additional damage or leave you stranded.
How Much Does It Cost to Fix P0720?
| Repair Task | Estimated Cost (USD) |
|---|---|
| Output Speed Sensor Replacement | $75 – $150 |
| Wiring or Connector Repair | $50 – $200 |
| Transmission Fluid Flush | $80 – $250 |
| PCM/TCM Replacement | $300 – $1,000 |
P0720 Code in Popular Models
🔧 PO720 Ford F-150
Known for faulty output speed sensors and connector corrosion. An easy sensor swap often solves the issue.
🔧 PO720 Infiniti Q50 / G20
Typically linked to issues with CVT transmission fluid or electronic TCM failures.
🔧 P0720 Nissan Altima / Maxima
Sensor placement in these models is sensitive to road debris and moisture intrusion, making regular inspection essential.
Related Diagnostic Codes
Internal linking helps readers explore more DTCs related to PO720:
- P0010 Code – Camshaft Position Actuator A
- P0012 Code – Camshaft Timing Retarded
- P0013 Code – Exhaust Camshaft Control
- P0014 Code – Camshaft Timing Over-Advanced
- P0456 Code – EVAP System Small Leak
- P0430 Code – Catalyst System Efficiency Below Threshold
Frequently Asked Questions (FAQs) About the P0720 Code
What does the P0720 code mean?
It indicates a malfunction in the output speed sensor circuit, often due to a failing sensor or wiring issue.
Can dirty transmission fluid cause P0720?
Yes. Dirty or low transmission fluid can lead to poor sensor readings and trigger this code.
How long can I drive with the P0720 code?
Driving is possible but not recommended, as you may experience shifting problems or further transmission damage.
Can I fix the P0720 code myself?
If you’re familiar with basic car diagnostics and tools, replacing the output speed sensor is usually a DIY-friendly job.
Is PO720 related to the speedometer?
Yes. A faulty output speed sensor can cause the speedometer to stop working or show inaccurate readings.