U0400 — Invalid/Lost Communication With Engine Control Module/Powertrain Control Module 'A'

Q: What does fault code U0400 mean?

U0400 means: Invalid/Lost Communication With Engine Control Module/Powertrain Control Module 'A'. It is a Network (CAN bus, communication) fault code defined by the OBD-II standard.

Q: Can I keep driving with U0400?

With U0400 you can usually drive home and book an inspection within a few days unless the car feels abnormal.

Network (CAN bus, communication)

Invalid/Lost Communication With Engine Control Module/Powertrain Control Module 'A'

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Can I drive with U0400?

You can usually drive home and book an inspection within a few days.

Frequently asked questions

What does fault code U0400 mean?

U0400 means Invalid/Lost Communication With Engine Control Module/Powertrain Control Module 'A'.

Can I keep driving with U0400?

You can usually drive home and book an inspection within a few days.

Related fault codes

U0401 — Invalid Data Received From ECM/PCM "A"
U0402 — Invalid Data Received From Transmission Control Module
U0403 — Invalid Data Received From Transfer Case Control Module
U0404 — Invalid Data Received From Gear Shift Control Module
U0405 — Invalid Data Received From Cruise Control Module
U0406 — Invalid Data Received From Fuel Pump Control Module
U0407 — Invalid Data Received From Glow Plug Control Module
U0408 — Invalid Data Received From Throttle Actuator Control Module
U0409 — Invalid Data Received From Alternative Fuel Control Module

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