Diagnose and Repair: Ford Expedition Transmission Output Speed Sensor

Ford Expedition Transmission Output Speed Sensor Diagnosis and Repair

Is your Ford Expedition experiencing erratic speedometer readings, rough shifting, or is the check engine light on? These are common symptoms of a failing transmission output speed sensor. But don't worry, this guide will walk you through diagnosing and fixing the issue.

Identifying the Problem

The transmission output speed sensor monitors the rotational speed of the output shaft and sends this information to the powertrain control module (PCM). A malfunctioning sensor can disrupt various transmission functions. Here's what to look for:

Symptoms:

• Erratic or inaccurate speedometer readings

• Difficulty shifting gears

• Transmission slipping

• Check Engine Light (CEL) illumination

Diagnosis:

A scan tool can be used to read diagnostic trouble codes (DTCs) stored in the PCM. Common codes related to the output speed sensor include:

• P0720: Output Speed Sensor Circuit Malfunction

• P0721: Output Speed Sensor Range/Performance

• P0722: Output Speed Sensor No Signal

Sensor Inspection:

• Locate the sensor on the transmission case, usually near the output shaft.

• Inspect the sensor and its wiring harness connector for visible damage, such as cracks, corrosion, or loose connections.

Fixing the Problem

Once you've identified a potential problem with the output speed sensor, these steps will help you fix it:

Testing:

Consult your vehicle repair manual for the proper procedure to test the output speed sensor. This typically involves using a multimeter to measure the sensor's resistance and compare it to the manufacturer's specifications.

Cleaning:

If the sensor's resistance is within spec, but you suspect a connectivity issue, you can try cleaning the sensor's electrical connector and the corresponding terminals on the vehicle's wiring harness. Use electrical contact cleaner and ensure the connection is secure.

Replacement:

If testing reveals the sensor is faulty, it needs to be replaced. Refer to your vehicle repair manual for specific instructions on how to remove and replace the sensor. When installing the new sensor, ensure it is properly seated and the mounting bolts are tightened to the manufacturer's specified torque.

Reset:

After replacing the sensor, use your scan tool to clear any stored diagnostic trouble codes.

Test Drive:

Take your vehicle for a test drive to verify the speedometer is functioning correctly and the transmission is shifting smoothly.

Extra Tips

• Consult a qualified mechanic if you're unsure about any step in the process.

• Always refer to your vehicle's service manual for specific instructions and torque specifications.

• While addressing the output speed sensor, it's a good practice to check your transmission fluid level and condition, as proper fluid level and quality are essential for optimal transmission operation.

Remember that performing proper maintenance and addressing potential problems early on can help extend the life of your Ford Expedition's transmission and keep your vehicle running smoothly for miles to come!

Visit prebuilttrans.com to learn more about our services or to schedule an appointment or call +1 385-462-8458 for more info! We're dedicated to keeping your pick-up truck running in tip-top shape!

Disclaimer: This blog post is intended for informational purposes only and should not be interpreted as professional advice. Always consult with a qualified mechanic or transmission specialist for specific recommendations regarding your vehicle.

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