NetworkU3012

Serious

Severity: Serious - have it checked soon

Control Module Improper Wake-up Performance

12 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 12

Brand	Code	Description	System
Ashok Leyland CV	U3012	Control Module Improper Wake-up Performance SAE	Network
Chery	U3012	BCM and Airbag Module (ABM) communication lost Brand	Network
Daewoo	U3012	Control Module Improper Wake-up Performance SAE	Network
DFFS	U3012	Startup failed Brand	Network
EOBD	U3012	Kontrollmodul feil oppvåkningsytelse Brand	Network
GM	U3012	Control Module Improper Wake-up Performance SAE	Network
Holden	U3012	Control Module Wake-Up Circuit Performance Brand	Network
Land Rover	U3012	Control Module Improper Wake-up Performance SAE	Network
Opel	U3012	Control Module Improper Wake-up Performance SAE	Network
Peugeot	U3012	Control Module Improper Wake-up Performance SAE	Network
Saab	U3012	Control Module Improper Wake-up Performance SAE	Network
Toyota	U3012	Startup failed 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 3

These 7-character codes are manufacturer-specific variants of U3012 and may be reported by some scan tools.

Brand	Code	Description	System
Mercedes-Benz	U301200	Control Module Improper Wake-up Performance Brand	Network
Mercedes-Benz	U301201	Control Module Improper Wake-up Performance. General Electrical Failure Brand	Network
Mercedes-Benz	U301254	Control Module Improper Wake-up Performance. Calibration is missing. Brand	Network

6Related codes

Browse Uxxx codes or U301xx codes.