Chevrolet Cobalt no crank no start issue after replacing TCM and computer with possible key relearn needed on Chevrolet Cobalt

Some Chevrolet Cobalt owners report experiencing a no crank, no start issue after replacing the TCM and computer, which may necessitate a key relearn procedure. Common symptoms include hearing only one click when attempting to start the vehicle, indicating potential issues with the starting system. Additionally, some owners have noted that if the positive battery jump start post cover is missing, contact with the TCM can lead to damage and require replacement. Excessive clicking from multiple relays and error codes related to lost connections to the TCM may also signal problems with the TCM or its components. Even after verifying Ohms readings and ensuring the CANBUS system is functioning, some vehicles still fail to start, suggesting deeper underlying issues that need further diagnosis. If the relay isn't receiving a signal to crank the engine despite fuel being present, this could indicate additional complications that require attention. It is crucial for owners to address these issues to ensure proper operation of the vehicle after component replacements.