U0408

Invalid Data Received from Vehicle Immobilizer Control Module

Moderate severity

The ECU receives an authorisation message from the immobilizer that does not match the expected rolling code. Engine start is blocked.

Common causes

Key not properly learned
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $90-880
Software version mismatch
A plausible cause — test and verify before replacing parts.
medium
Typical part cost: $90-880
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First things to check

1Confirm the code with a scan tool and check for additional related codes.
2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

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Related codes

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Frequently asked questions

What does U0408 mean?

U0408 means "Invalid Data Received from Vehicle Immobilizer Control Module". It is a generic OBD-II code that points to a fault in the network / communication.

What are the most common causes of U0408?

key not properly learned; software version mismatch; gateway module routing can messages incorrectly — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.

Can I keep driving with this code?

The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.

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