NetworkU0101

Serious

Severity: Serious - have it checked soon

Lost Communication With Transmission Control Module

42 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 42

Brand	Code	Description	System
Ashok Leyland CV	U0101	Lost Communication With Transmission Control Module SAE	Network
BAIC Motor	U0101	CAN TCM Communication Brand	Network
Mercedes-Benz	U0101	Lost Communication With Transmission Control Module SAE	Network
BYD	U0101	Lost Communication with TCM Brand	Network
Chery	U0101	TCU CAN message Brand	Network
Daewoo	U0101	Lost Communication with TCM Brand	Network
Daihatsu	U0101	AT/CVT reception fault Brand	Network
DFFS	U0101	Gear signal lost Brand	Network
DFFX	U0101	Lost Communication with TCM Brand	Network
DFXK	U0101	Lost Communication with TCM Brand	Network
EOBD	U0101	Kaotatud side TCM-ga Brand	Network
Ford	U0101	TCM DTC: Not detected Brand	Network
Geely	U0101	Lost Communication with TCM Brand	Network
GM	U0101	Lost Communication with TCM Brand	Network
Great Wall	U0101	Lost Communication with TCM Brand	Network
Hafei	U0101	Lost Communication with TCM Brand	Network
Holden	U0101	Lost Communication with Transmission Control Module Brand	Network
Honda	U0101	Automatic Transmission (CVT) Control Unit (PGM-FI ECU) Communication Anomaly (Radar Vision Unit) Fault Location and Cause Estimation Automatic Transmission (CVT) Control Unit Fault CAN Gateway Fault CAN Line Open Circuit/Short Circuit Laser Radar Brand	Network
Hyundai	U0101	Lost Communication With Transmission Control Module SAE	Network
Isuzu	U0101	Lost Communication With Transmission Control Module SAE	Network
Land Rover	U0101	Lost communications with transmission control module Brand	Network
Mahindra	U0101	Lost Communication With Transmission Control Module SAE	Network
Maserati	U0101	Lost Communication with Transmission Control Module-Bus Signal / Message Failures Brand	Network
Mazda	U0101	TCM DTC: Not detected Brand	Network
Mitsubishi	U0101	T/M CAN timeout Brand	Network
Nissan	U0101	Lost Communication With Transmission Control Module SAE	Network
Opel	U0101	Lost Communication with TCM Brand	Network
Perodua	U0101	AT/CVT reception fault Brand	Network
Peugeot	U0101	Lost Communication With Transmission Control Module SAE	Network
Porsche	U0101	Lost Communication With Transmission Control Module SAE	Network
Proton	U0101	T/M CAN timeout Brand	Network
Saab	U0101	Lost Communication with TCM Brand	Network
Maxus (SAIC)	U0101	Lost Communication With SCU Brand	Network
MG (SAIC)	U0101	TCM Time Out Brand	Network
Smart	U0101	Lost Communication With Transmission Control Module SAE	Network
Sprinter	U0101	Lost Communication With Transmission Control Module SAE	Network
Subaru	U0101	Lost Communication With Transmission Control Module SAE	Network
Suzuki	U0101	Lost Communication with TCM: Not detected Brand	Network
SWM Motor	U0101	EMS lost communication with TCU Brand	Network
Tata	U0101	Lost Communication With TCM Brand	Network
Toyota	U0101	Communication with TCU lost Brand	Network
Volkswagen	U0101	No Communication with Transmission Control Module 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 15

These 7-character codes are manufacturer-specific variants of U0101 and may be reported by some scan tools.

Brand	Code	Description	System
Mercedes-Benz	U010100	Timeout for TCM messages Brand	Network
Hyundai	U010100	The PCM determines CAN communication error and sets DTC if no message received from TCM Brand	Network
Porsche	U010100	No description available	Network
SsangYong	U010100	CAN: TCU Message(GS218) not Received (Time Out) Brand	Network
Mercedes-Benz	U010102	Communication with control unit 'Transmission' has a malfunction. There is a general signal fault. Brand	Network
Mercedes-Benz	U010164	Communication with control unit 'Transmission' has a malfunction. Signal Plausibility Failure. Brand	Network
Mercedes-Benz	U010186	Communication with control unit 'Transmission' has a malfunction. Signal invalid. Brand	Network
Mercedes-Benz	U010187	Timeout of TCM messages Brand	Network
SsangYong	U010187	CAN communication: Vehicle Control Unit (VCU) message not received Brand	Network
SsangYong	U010195	CAN communication error (BMS 1D9h) Brand	Network
SsangYong	U010196	CAN communication error (BMS 1D5h) Brand	Network
SsangYong	U010197	CAN communication error (VCU 3AEh) Brand	Network
SsangYong	U010198	CAN bus error Brand	Network
SsangYong	U010199	CAN communication: E-CAN no communication - bus off Brand	Network
Mercedes-Benz	U0101FC	SG TCM_Data3_Pr2 - Timeout Error Brand	Network

6Related codes

Browse Uxxx codes or U010xx codes.