NetworkU0120

Serious

Severity: Serious - have it checked soon

Lost Communication With Starter / Generator Control Module

35 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

Safety: This code relates to the charging system. The battery may go flat and the car may stall.

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 35

Brand	Code	Description	System
Ashok Leyland CV	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
BAIC Motor	U0120	ECU lost communication with BSG control module Brand	Network
Mercedes-Benz	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
BYD	U0120	Lost Communication With Starter/Generator Control Module Brand	Network
Chery	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
Chrysler	U0120	lost communication with starter/generator control module Brand	Network
Daewoo	U0120	Lost Communication With Starter/Generator Control Module Brand	Network
Daihatsu	U0120	Push start communication fault Brand	Network
DFFS	U0120	Communication lost with starter/generator control module Brand	Network
DFFX	U0120	Lost Communication With Starter/Generator Control Module Brand	Network
DFXK	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
EOBD	U0120	Kaotatud side starteri/generaatori juhtimismooduliga Brand	Network
Geely	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
GM	U0120	Lost Communication With Starter/Generator Control Module Brand	Network
Great Wall	U0120	Lost Communication With Starter/Generator Control Module Brand	Network
Hafei	U0120	Lost Communication With Starter/Generator Control Module Brand	Network
Holden	U0120	Lost Communication with Starter/Generator Control Module Brand	Network
Hyundai	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
Isuzu	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
Land Rover	U0120	Lost communication with the starter/generator control module Brand	Network
Maserati	U0120	Lost Communication With Starter/Generator Control Module Brand	Network
Mitsubishi	U0120	GCU CAN timeout Brand	Network
Opel	U0120	Lost Communication With Starter/Generator Control Module Brand	Network
Perodua	U0120	Push start communication fault Brand	Network
Peugeot	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
Proton	U0120	GCU CAN timeout Brand	Network
Saab	U0120	Lost Communication With Starter/Generator Control Module Brand	Network
Maxus (SAIC)	U0120	Lost Communication With LDW Brand	Network
MG (SAIC)	U0120	Lost Communication With ISC Brand	Network
Smart	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
Sprinter	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
Subaru	U0120	Lost Communication With Starter / Generator Control Module SAE	Network
Suzuki	U0120	STR/GEN C/M Brand	Network
Toyota	U0120	Communication between ECM and system power control module (C120) lost Brand	Network
Volkswagen	U0120	Lost Communication With Starter / Generator Control Module SAE	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.

5Related codes

Browse Uxxx codes or U012xx codes.