Code U0100 in 2015 Chevrolet Silverado - No Start After Battery Reconnection
I'm helping a friend who recently picked up a wrecked 2015 Chevrolet Silverado. The vehicle sustained front-end damage with blown airbags, but no engine damage. He drove it to his trailer and parked it in his driveway. After removing the battery and sitting for several months, he reconnected it to try starting the truck. However, when he turned the key, there was no response — neither a start nor any crank sound. He had a friend scan the vehicle and found only code U0100, with no other issues reported. He later replaced the ECM with a used one, but the problem persists. No changes in behavior or diagnostics have occurred since. The truck shows no signs of electrical or engine failure, just front-end structural damage. Any insights into what could be causing this U0100 code and why the vehicle won't start after reconnection? Is it possible that the ECM swap didn’t resolve the issue due to a deeper underlying problem?
Clear all stored codes using an OBD2 scanner and scan every module on the vehicle's network. Check if the U0100 code returns after clearing. Also, confirm exactly what issue you're experiencing — is it no start at all? No crank? No spark? This will help narrow down whether the problem lies in the powertrain, electrical system, or a specific sensor. Ensure the battery is properly connected and grounded, as poor connections can trigger diagnostic codes or prevent starting.