U1651 – Invalid or Missing Data for Vehicle Speed.

The ODBII code U1651 indicates that the vehicle’s control module has detected invalid or missing data related to vehicle speed, which may affect the performance of various systems.

The severity of ODBII code U1651 is moderate.

Common Causes For: U1650 U1650: “Module Communication Failure”

• Faulty vehicle speed sensor
• Damaged wiring or connectors
• Poor ground connection
• Malfunctioning engine control module (ECM)
• Issues with the transmission control module (TCM)
• Faulty ABS module
• Corrupted data communication between modules
• Software glitches or updates needed in the vehicle’s control modules

Common misdiagnosis for U1651 Invalid or Missing Data for Vehicle Speed.

• Faulty Vehicle Speed Sensor (VSS)
• Malfunctioning Engine Control Module (ECM)
• Wiring issues or shorts in the speed sensor circuit
• Faulty ABS module
• Incorrect tire size or calibration issues
• Problems with the transmission control module (TCM)
• Issues with the instrument cluster
• Faulty or corroded connectors and terminals

Common Troubleshooting Steps

The OBD-II code U1651 indicates an “Invalid or Missing Data for Vehicle Speed.” This code typically points to a communication issue between the vehicle’s modules, particularly related to the vehicle speed sensor (VSS) or the data being transmitted over the CAN (Controller Area Network) bus. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. Codes related to the transmission, speed sensor, or other modules can provide additional context.
• Inspect Vehicle Speed Sensor (VSS): Locate the vehicle speed sensor and inspect it for any physical damage or disconnection.
• Check the wiring and connectors for corrosion, fraying, or loose connections.
• Test the VSS with a multimeter to ensure it is functioning correctly. Refer to the vehicle’s service manual for specific resistance values.
• Examine Wiring and Connectors: Inspect the wiring harnesses and connectors associated with the VSS and the modules that communicate vehicle speed data.
• Look for any signs of wear, damage, or poor connections that could affect data transmission.
• Check the CAN Bus: Use a scan tool to monitor the CAN bus for any communication issues. Ensure that all modules are communicating properly.
• Check for any short circuits or open circuits in the CAN wiring.
• Inspect the Instrument Cluster: If the vehicle speed data is not being displayed correctly on the instrument cluster, there may be an issue with the cluster itself.
• Check for any faults in the cluster that could prevent it from receiving or displaying speed data.
• Test the PCM/ECM: The Powertrain Control Module (PCM) or Engine Control Module (ECM) may be at fault. Check for software updates or reprogramming needs.
• If other modules are not receiving data from the PCM, it may need to be tested or replaced.
• Clear Codes and Test Drive: After performing inspections and repairs, clear the trouble codes using the OBD-II scanner.
• Take the vehicle for a test drive to see if the code reappears. Monitor the vehicle speed data during the drive.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the U1651 code or vehicle speed sensor issues for your specific make and model. Manufacturers may have known fixes or updates.
• Professional Diagnosis: If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized tools and knowledge to diagnose complex communication issues. By following these troubleshooting steps, you should be able to identify and resolve the underlying issue causing the U1651 code.