u1003 lost communication with vvel control module

OBD2 Code: U1003

Description: Lost Communication with VVEL Control Module

Definition: This code indicates that the vehicle’s main computer (Powertrain Control Module or PCM) has lost communication with the Variable Valve Event and Lift (VVEL) control module. The VVEL system is responsible for optimizing engine performance by adjusting valve timing and lift.

– Severity: Critical

Common Causes

U1003 – Lost Communication with VVEL Control Module

Common Causes:

• Faulty VVEL control module
• Wiring issues such as damaged wires or poor connections
• Interference from other electronic devices
• Software issues in the vehicle’s computer system

 

Common Misdiagnosis

Lost Communication with VVEL Control Module – Common Misdiagnosis: Faulty wiring or connectors are often misdiagnosed as a failed VVEL control module.

 

Common Diagnostic Steps

Lost Communication with VVEL Control Module

1. Check the vehicle’s battery voltage and ensure it is within the specified range.
2. Inspect all related fuses for the VVEL control module and replace any that are blown.
3. Examine the wiring harness and connectors between the Engine Control Module (ECM) and the VVEL control module for any signs of damage, corrosion, or disconnection.
4. Use a scan tool to check for additional diagnostic trouble codes (DTCs) that may indicate other issues affecting communication.
5. Perform a continuity test on the CAN bus lines connected to the VVEL control module to ensure there are no open circuits or short circuits.
6. If equipped, update or reprogram the ECM software as per manufacturer recommendations.
7. If all checks pass but the issue persists, consider replacing the VVEL control module after verifying its failure through proper testing procedures.