what does the U1120 code mean on my Ford F-150 13th Generation (2015-2020)

Ford F-150 13th Generation (2015-2020)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

Error Code: U1120

3 min read

462 words

Problem Statement

Learn how to diagnose and fix U1120 lost communication with vehicle speed module in Ford F-150 (2015-2020). Step-by-step guide with diagnostic procedures.

Error Code

U1120

Affected Component

Electrical

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical components to ensure safety.

Symptoms

•Check engine light illuminated
•Erratic speedometer readings
•Inaccurate fuel economy display
•Unresponsive or malfunctioning electronic features
•Possible transmission shifting issues

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm U1120 and any other related codes.
2
Inspect the vehicle's wiring harness and connectors for damage, corrosion, or loose connections.
3
Check the Vehicle Speed Sensor (VSS) for proper operation and wiring continuity.
4
Verify the operation of the instrument cluster and related modules for communication errors.
5
Test the battery voltage and ground connections to ensure proper power supply to the modules.
6
Perform a network scan to identify any other communication faults within the CAN bus system.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Multimeter
•Socket set
•Torque wrench
•Screwdriver set

Parts Required

•Vehicle Speed Sensor (if replacement is needed)

Related Faults

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm U1120 and any other related codes.
2
Inspect the vehicle's wiring harness and connectors for damage, corrosion, or loose connections.
3
Check the Vehicle Speed Sensor (VSS) for proper operation and wiring continuity.
4
Verify the operation of the instrument cluster and related modules for communication errors.
5
Test the battery voltage and ground connections to ensure proper power supply to the modules.
6
Perform a network scan to identify any other communication faults within the CAN bus system.

Solution

1. Preparation

Gather tools and parts needed.
Disconnect the battery to ensure safety while working on electrical components.

2. Inspect Wiring and Connectors

Use a multimeter to check for continuity and proper voltage at the Vehicle Speed Sensor (VSS) connector.
Inspect the wiring harness for any visible damage or fraying.
Clean and secure any corroded or loose connections.

3. Replace the Vehicle Speed Sensor (if faulty)

Locate the Vehicle Speed Sensor (usually found on the transmission).
Remove the sensor:
- Disconnect the electrical connector.
- Remove the retaining bolt using a socket set.
Install the new sensor:
- Apply a small amount of thread sealant to the new sensor threads.
- Install the sensor and torque the retaining bolt to manufacturer specifications (consult service manual for torque value).
- Reconnect the electrical connector.

4. Clear Codes and Test

Reconnect the battery.
Use the OBD-II scanner to clear the U1120 code and any other related codes.
Conduct a test drive to ensure the vehicle operates correctly and monitor for reoccurrence of the code.