NetworkU1031

Serious

Severity: Serious - have it checked soon

Loss of Serial Communications for Class 2 Devices

17 brands affected · Description from GM data.

Key terms: Control module: a small computer that runs one part of the car

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 17

Brand	Code	Description	System
BAIC Motor	U1031	Gasoline Particulate Filter (GPF) differential pressure sensor communication fault Brand	Network
Mercedes-Benz	U1031	No description available	Network
Chery	U1031	Gateway lost communication with CAN 3 network segment Passive Entry Passive Start Brand	Network
Daewoo	U1031	Loss of Serial Communications for Class 2 Devices Brand	Network
DFFS	U1031	EMS2 (0x300) communication lost Brand	Network
DFFX	U1031	Gasoline Particulate Filter (GPF) Differential Pressure Sensor Communication Error Brand	Network
DFXK	U1031	Gasoline Particulate Filter (GPF) differential pressure sensor communication error Brand	Network
EOBD	U1031	FlexRay-databus Brand	Network
GM	U1031	Loss of Serial Communications for Class 2 Devices Brand	Network
Isuzu	U1031	No description available	Network
Mahindra	U1031	No description available	Network
Peugeot	U1031	No description available	Network
Saab	U1031	Loss of Serial Communications for Class 2 Devices Brand	Network
MG (SAIC)	U1031	Lost Communication With Infotainment Faceplate Module Brand	Network
Smart	U1031	No description available	Network
Sprinter	U1031	No description available	Network
Tata	U1031	No description available	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 U1031 and may be reported by some scan tools.

Brand	Code	Description	System
Mercedes-Benz	U103100	No description available	Network
Volkswagen	U103100	FlexRay data bus no synchronisation Brand	Network

6Related codes

Browse Uxxx codes or U103xx codes.