What does code U300A mean?

Q: What does code U300A mean?

Ignition Switch. U300A is a generic body code indicating that a control module has detected a fault in the ignition switch circuit, meaning the module is not receiving the expected voltage signals that confirm the switch is in the correct position. The computer sets this code when the ignition switch input does not match the expected state, often due to a wiring, connection, or switch internal failure.

DTC codes / U30xx · Network wiring and bus faults / U300A

U300AIgnition Switch

U300A is a generic body code indicating that a control module has detected a fault in the ignition switch circuit, meaning the module is not receiving the expected voltage signals that confirm the switch is in the correct position. The computer sets this code when the ignition switch input does not match the expected state, often due to a wiring, connection, or switch internal failure.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaNetwork wiring and bus faults

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.