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U0427: The alarm system control unit sends invalid data

The alarm system control unit sends invalid data. This often comes from a fault in that unit or outdated software.

Code U0427 at a glance
CodeU0427
SystemCommunication network
GroupU04xx, Invalid data between control units
TypeGeneric: it means the same on every make

How to read and clear U0427 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see U0427 with its description and whether it’s confirmed, pending or permanent.

If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.

Similar codes

What does code U0427 mean?

The alarm system control unit sends invalid data. This often comes from a fault in that unit or outdated software.

How do you clear U0427?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, U0427 comes back.