U0499 High Generic / SAE

U0499: Invalid Data Received From Telematic Control Module

Network and Communication Invalid Data Received

What to do

Do not treat this as "just the connected services", because one of the things it takes with it is the car's automatic emergency call.

Since 2018 every new car in the EU has been required to carry a system that calls the emergency services by itself after a serious crash, gives them your exact position, and opens a voice line — whether or not anyone in the car can speak. This module is that system, along with breakdown calling, stolen vehicle tracking and the phone app.

Nothing about driving changes, there is no symptom, and that is exactly the problem. The only moment you would find out it was gone is the one moment it existed for.

Two of the common causes are worth knowing before you are quoted for anything.

If the car is seven years old or more, ask about the backup battery. The emergency call system carries its own small battery so it can still call after the main one has been destroyed in a crash. Those wear out on a timescale, like a smoke alarm battery, and replacing one is a routine and reasonably cheap job.

Ask whether the mobile network it uses still exists. Older 2G and 3G networks are being switched off country by country, and a module built for those simply has nothing to connect to. No repair fixes that. Some manufacturers offer an upgrade and some do not — you are entitled to a straight answer on which, rather than a diagnostic bill.

Finally, if you bought the car used, ask whether the telematics has been deliberately disabled. Some owners switch it off over data privacy, which is their choice — but whoever drives it next should know that the automatic emergency call went with it.

What this code means

The telematics control module is broadcasting data that cannot be accepted as true. See U0400 for the family's framing.

This is the vehicle's own mobile connection — its own SIM, its own aerial and, importantly, its own battery — and it does one job that justifies the severity on this page.

Automatic emergency calling. Every new car type-approved in the European Union since 2018 must carry it, and equivalents exist elsewhere. When a crash severe enough to deploy the restraints occurs, the vehicle calls the emergency number by itself, transmits its exact position, direction of travel and the number of belted occupants, and opens a voice channel — whether or not anybody inside is conscious or able to speak.

The failure is completely invisible, and that is the argument for treating it seriously. Nothing about driving changes. There is no symptom. The absence only becomes apparent at the single moment it was installed for, which is why "it is only the connected services" is the wrong reading of this code.

Alongside that the module normally provides breakdown calling, stolen vehicle tracking, remote locking and preconditioning from an app, over-the-air software updates, and on newer vehicles the data used for servicing and insurance.

Four causes, and two of them are not repairable in the ordinary sense.

The backup battery has aged out. An emergency call module carries a small internal cell so that it can still call after the vehicle's own battery has been destroyed in the impact. Those cells are consumables with a service life of several years, and a telematics fault on a vehicle seven or more years old is very often exactly this. It is a replacement item rather than a failure, and it is not expensive.
The mobile network the module was built for has been switched off. 2G and 3G networks are being decommissioned market by market, and a module that speaks only those simply has nothing to connect to. No repair changes that — some manufacturers offered a hardware upgrade and some did not, and an owner is entitled to a straight answer about which applies rather than a diagnostic bill.
The aerial, which is the roof antenna module at U0486 and its connectors, disturbed by headlining work.
An aftermarket tracker, insurance box or dashcam spliced into the same circuits, which is where such devices are most often fitted.

One further point belongs on this page as a matter of fact rather than opinion. This module is what makes the vehicle's position, movement and use available off the vehicle, and an owner is entitled to know that, to know what their manufacturer's services do with it, and to know what is switched off if the module is disconnected. A telematics module that has been deliberately disabled — by a previous owner or a workshop — is a real cause of this code, and the person now driving the vehicle should be told that the emergency call function went with it.

Likely causes

Start here

GPS antenna disconnected or damaged · moderate
Module not coded to the vehicle · specialist
Poor wiring splice in an aftermarket installation · moderate
Corroded or loose connector · easy

Less common

Software calibration out of date · specialist
Damaged data bus wiring · moderate

Symptoms

Components involved

Information, not instruction

CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.

Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

Community experience

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