NetworkU0074

Serious

Severity: Serious - have it checked soon

Control Module Communication Bus B Off

34 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

Wiring or connector fault on the communication bus
Faulty control module
Low battery voltage or poor ground
Water ingress in a connector or module
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 34

Brand	Code	Description	System
Ashok Leyland CV	U0074	Control Module Communication Bus B Off SAE	Network
BAIC Motor	U0074	CAN1 Bus Malfunction Brand	Network
BYD	U0074	Control Module Communication Bus 'B' Off Brand	Network
Chery	U0074	Vehicle CAN bus off Brand	Network
Chrysler	U0074	Control Module Communication Bus B Off SAE	Network
Daewoo	U0074	Control Module Communication Bus B Off SAE	Network
Daihatsu	U0074	CAN gateway BUS4 communication error Brand	Network
DFFS	U0074	All nodes lost Brand	Network
DFFX	U0074	Control Module Communication Bus 'B' Off Brand	Network
DFXK	U0074	Control Module Communication Bus 'B' Off Brand	Network
EOBD	U0074	Juhtmoduli sidebuss 'B' väljas Brand	Network
Fiat	U0074	Dedicated powertrain (D-PT) CAN Bus off Brand	Network
Ford	U0074	Control Module Communication Bus B Off SAE	Network
Geely	U0074	Control Module Communication Bus 'B' Off Brand	Network
GM	U0074	Control Module Communication Bus 'B' Off Brand	Network
Great Wall	U0074	Control Module Communication Bus 'B' Off Brand	Network
Hafei	U0074	Control Module Communication Bus 'B' Off Brand	Network
Holden	U0074	CAN Bus Communication Brand	Network
Honda	U0074	Control Module Communication Bus B Off SAE	Network
Hyundai	U0074	Control Module Communication Bus B Off SAE	Network
Isuzu	U0074	Control Module Communication Bus B Off SAE	Network
Land Rover	U0074	Control Module Communication Bus B Off SAE	Network
Maserati	U0074	Dedicated Powertrain (D-PT) CAN bus off Brand	Network
Mitsubishi	U0074	Control Module Communication Bus B Off SAE	Network
Opel	U0074	Control Module Communication Bus 'B' Off Brand	Network
Perodua	U0074	CAN gateway BUS4 communication error Brand	Network
Peugeot	U0074	Control Module Communication Bus B Off SAE	Network
Saab	U0074	Control Module Communication Bus 'B' Off Brand	Network
Maxus (SAIC)	U0074	CH CAN bus off Brand	Network
MG (SAIC)	U0074	CH bus off Brand	Network
Subaru	U0074	Control Module Communication Bus B Off SAE	Network
Suzuki	U0074	Error status of own ECU CAN node Brand	Network
Tata	U0074	Control Module Communication Bus B Off SAE	Network
Toyota	U0074	Control module communication bus 'B' off Brand	Network

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 2

These 7-character codes are manufacturer-specific variants of U0074 and may be reported by some scan tools.

Brand	Code	Description	System
Mercedes-Benz	U007400	OBD relevant DTC in RBS. For detailed information read Fault Memory of RBS Brand	Network
Hyundai	U007400	If P-CAN Bus off is detected, ECM sets DTC. This fault might be caused by short in P-CAN communication circuit Brand	Network

6Related codes

Browse Uxxx codes or U007xx codes.