Fault code lookup

NetworkU0400

Serious

Severity: Serious - have it checked soon

Invalid Data Received

29 brands affected · Generic SAE J2012 description.

Key terms: Control module: a small computer that runs one part of the car · SAE J2012: the standard generic code list

1What it means in plain English

Control modules in the car cannot communicate with each other over the vehicle network.

2Common causes

  1. Wiring or connector fault on the communication bus
  2. Faulty control module
  3. Low battery voltage or poor ground
  4. Water ingress in a connector or module
  5. Aftermarket device interfering with the bus

3Can I drive?

Serious · drive with care

The car may run normally or may not run at all. If the module that has lost communication controls steering, brakes, park brake, charging or engine cooling, drive only if those systems feel normal; stop safely if the steering becomes heavy, a brake warning appears, or the engine temperature climbs. If the car will not start or runs badly, have it towed.

This page gives general information. It is not professional advice. For a definite diagnosis and a repair quote, ask a qualified mechanic to inspect the car.

4Brand data 29

BrandCodeDescriptionSystem
Ashok Leyland CVU0400Invalid Data Received SAENetwork
BAIC MotorU0400Invalid Data Received BrandNetwork
BYDU0400Invalid Data Received BrandNetwork
CheryU0400Invalid Data Received BrandNetwork
DaewooU0400Invalid Data Received BrandNetwork
DFFSU0400Invalid Data Received BrandNetwork
DFFXU0400Invalid Data Received BrandNetwork
DFXKU0400Invalid Data Received BrandNetwork
EOBDU0400Ugyldig data mottatt BrandNetwork
GeelyU0400Invalid Data Received BrandNetwork
GMU0400Invalid Data Received BrandNetwork
Great WallU0400Invalid Data Received BrandNetwork
HafeiU0400Invalid Data Received BrandNetwork
HoldenU0400Invalid Data Received BrandNetwork
HondaU0400Invalid Data Received SAENetwork
HyundaiU0400Invalid Data Received SAENetwork
IsuzuU0400Invalid Data Received SAENetwork
Land RoverU0400Invalid Data Received SAENetwork
MitsubishiU0400Invalid Data Received SAENetwork
NissanU0400Invalid Data Received SAENetwork
OpelU0400Invalid Data Received BrandNetwork
PeugeotU0400Invalid Data Received SAENetwork
ProtonU0400Invalid Data Received SAENetwork
SaabU0400Invalid Data Received BrandNetwork
MG (SAIC)U0400Invalid Data Received BrandNetwork
SuzukiU0400INVALID (HV ECU) BrandNetwork
TataU0400Invalid Data Received BrandNetwork
ToyotaU0400Invalid data received BrandNetwork
VolkswagenU0400SAE: Invalid Data Received BrandNetwork

Legend: SAE is the generic J2012 description; Brand is text taken from that manufacturer’s data. Manufacturer rows keep the wording and language of the source data, and non-English text is tagged so screen readers pronounce it correctly.

5Extended variant codes 5

These 7-character codes are manufacturer-specific variants of U0400 and may be reported by some scan tools.

BrandCodeDescriptionSystem
Mercedes-BenzU040029The received data are implausible. There is an invalid signal. BrandNetwork
Mercedes-BenzU040081The received data are implausible. Invalid Serial Data Received BrandNetwork
Mercedes-BenzU040085The received data are implausible. Signal Above Allowable Range BrandNetwork
Mercedes-BenzU040086No description available Network
SmartU040086No description available Network

6Related codes

Browse Uxxx codes or U040xx codes.

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