NetworkU1001

Serious

Severity: Serious - have it checked soon

CAN passive error

36 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 36

Brand	Code	Description	System
Ashok Leyland CV	U1001	No description available	Network
BAIC Motor	U1001	CAN module initialized HS CAN Brand	Network
Mercedes-Benz	U1001	No description available	Network
BYD	U1001	Communication line error Brand	Network
Chery	U1001	BCM confirmed absent state Brand	Network
Daewoo	U1001	Loss of serial communications for class 2 devices Brand	Network
Daihatsu	U1001	EFI communication transmit abnormal Brand	Network
DFFS	U1001	CAN bus off Brand	Network
DFFX	U1001	CAN1 communication failure Brand	Network
DFXK	U1001	CAN error passive Brand	Network
EOBD	U1001	Bus CAN as Brand	Network
Ford	U1001	AEBS communication failure Brand	Network
Geely	U1001	Front Passenger Side Power Window LIN Communication Error Brand	Network
GM	U1001	Loss of serial communications for class 2 devices Brand	Network
Holden	U1001	CAN Bus Communication Brand	Network
Honda	U1001	No description available	Network
Hyundai	U1001	No description available	Network
Isuzu	U1001	No description available	Network
Land Rover	U1001	Switchpack - Switch circuit Brand	Network
Mahindra	U1001	No description available	Network
Maserati	U1001	No description available	Network
Mazda	U1001	AEBS communication failure Brand	Network
Mitsubishi	U1001	Variant coding mismatch Brand	Network
Opel	U1001	Loss of serial communications for class 2 devices Brand	Network
Perodua	U1001	EFI communication transmit abnormal Brand	Network
Peugeot	U1001	No description available	Network
Proton	U1001	Variant coding mismatch Brand	Network
Saab	U1001	Loss of serial communications for class 2 devices Brand	Network
MG (SAIC)	U1001	KBus Fault Brand	Network
Smart	U1001	No description available	Network
Sprinter	U1001	No description available	Network
Subaru	U1001	No description available	Network
Suzuki	U1001	High Speed CAN Communication Bus Brand	Network
SWM Motor	U1001	Speed speed timeout fault Brand	Network
Tata	U1001	No description available	Network
Toyota	U1001	CAN passive 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 U1001 and may be reported by some scan tools.

Brand	Code	Description	System
SsangYong	U100187	CAN bus: BCM no signal Brand	Network
SsangYong	U100188	CAN bus off Brand	Network

6Related codes

Browse Uxxx codes or U100xx codes.