1. Verify the Trouble Code:
- Connect an OBD-II scanner to your vehicle's diagnostic port.
- Turn the key to the "ON" position (do not start the engine).
- Retrieve any stored trouble codes. If you see the P0720 code, it confirms the Output Shaft Speed Sensor issue.
2. Locate the OSS:
- The Output Shaft Speed Sensor is usually located near the transmission's output shaft. In the 1996 Chrysler Town and Country, it's typically mounted on the side of the transmission.
3. Inspect the OSS Wiring:
- Check the wiring harness that connects the OSS to the transmission control module (TCM). Look for any signs of damage, corrosion, or loose connections. Repair or replace the wiring as needed.
4. Test the OSS:
- Disconnect the electrical connector from the Output Shaft Speed Sensor.
- Using a multimeter set to the resistance or ohms setting, measure the resistance between the sensor's terminals.
- The resistance value should fall within the specified range provided in your vehicle's service manual. If the resistance is out of range or the sensor shows no continuity, replace the OSS.
5. Clean the OSS Mounting Surface:
- If the Output Shaft Speed Sensor seems to be in good condition, clean the mounting surface where it attaches to the transmission. Dirt, grease, or metal shavings can affect the sensor's ability to read the shaft's speed accurately.
6. Reinstall the OSS and Reconnect Wiring:
- Reinstall the Output Shaft Speed Sensor, ensuring it's securely mounted and the electrical connector is properly connected.
7. Clear Trouble Codes:
- Reconnect the OBD-II scanner and clear any stored trouble codes, including P0720.
8. Test Drive the Vehicle:
- Take your vehicle for a test drive to see if the P0720 code reappears. If the issue persists, further diagnosis may be necessary, possibly involving the transmission control module or internal transmission components.
Remember that diagnosing and fixing transmission-related issues can be complex and may require specialized tools and knowledge. If you're not comfortable performing these steps yourself, it's best to consult a professional mechanic for assistance.
