NetworkU1211

Serious

Severity: Serious - have it checked soon

Engine parity/toggle bit error

14 brands affected · Description from Toyota 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 14

Brand	Code	Description	System
Chery	U1211	Lost communication with Battery Management System (BMS) module Brand	Network
Daewoo	U1211	Loss of serial communications for class 2 devices Brand	Network
DFFS	U1211	Lateral acceleration signal is invalid or out of range Brand	Network
EOBD	U1211	Ralat bit pariti/suis enjin Brand	Network
GM	U1211	Loss of serial communications for class 2 devices Brand	Network
Holden	U1211	No description available	Network
Mahindra	U1211	No description available	Network
Mitsubishi	U1211	ENG Parity/Toggle bit error Brand	Network
Opel	U1211	Loss of serial communications for class 2 devices Brand	Network
Peugeot	U1211	No description available	Network
Proton	U1211	ENG Parity/Toggle bit error Brand	Network
Saab	U1211	Loss of serial communications for class 2 devices Brand	Network
Subaru	U1211	No description available	Network
Toyota	U1211	Engine parity/toggle bit error 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 U1211 and may be reported by some scan tools.

Brand	Code	Description	System
Mercedes-Benz	U121101	SBC SPOC Fehler - General Electric Failure Brand	Network
SsangYong	U121183	CAN communication: Motor Control Unit (MCU) checksum error (1E2) Brand	Network

6Related codes

Browse Uxxx codes or U121xx codes.