U0404 High Generic / SAE

U0404: Invalid Data Received From Gear Shift Control Module A

Network and Communication Invalid Data Received

What to do

Use the parking brake firmly every time you stop, and do not rely on the gear display.

On your car the lever is not mechanically connected to the gearbox — it sends a request. This code means the module reading your lever is reporting a position the rest of the car cannot believe, usually because the lever is reading between positions or its backup sensors disagree.

So the car may refuse to come out of park, refuse to go into park, or show a gear it is not in. The last is the one that matters. If the car rolls at all when you take your foot off the brake, it is not in park regardless of what the display says — so use the parking brake and avoid slopes.

If a drink has been spilt into the centre console, say so. The selector lives there, and sticky residue bridging its contacts is a very common cause of exactly this — and it explains a fault that comes and goes.

What this code means

The gear shift control module is broadcasting a selector position that cannot be accepted as true. See U0400 for the family's framing and U0291 for what a shift-by-wire selector is.

This is one of the more consequential codes in the family, because the value in question is which gear the driver has asked for — and on a shift-by-wire vehicle that request is the only link between the lever and the gearbox.

An implausible selector report is usually one of two things, and both are worth knowing.

A position between detents. These selectors read a lever or rotary control through redundant sensors, and a reading that corresponds to no valid position — mid-way between drive and neutral — is rejected rather than guessed at. That is correct behaviour: guessing which gear a driver asked for is exactly what a safety-critical system must not do.

Or the redundant sensors disagreeing. Where two or three sensors watch the same lever precisely so that no single failure can be believed, one drifting out of agreement makes the whole reading untrustworthy — and the module publishes something the receivers reject.

The practical consequences are the ones set out at U0291 and they deserve repeating because they involve where the vehicle ends up parked. The vehicle may refuse to leave park, may refuse to select park, and the gear display may disagree with what is actually engaged — which is the dangerous version, because it is the one a driver acts on.

So: apply the parking brake deliberately every time, and do not trust the display. If the vehicle rolls when the brake pedal is released, it is not in park whatever the dashboard says.

The commonest physical cause is the one the corpus already names for centre-console electronics: spilt liquid. The selector sits in the console, and residue bridging contacts produces exactly the disagreeing-sensor picture — and explains the intermittent version.

Likely causes

Start here

Less common

Faulty receiving module input · 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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