U0514 Low Generic / SAE

U0514: Invalid Data Received From Mirror Control Module A

Network and Communication Invalid Data Received (continued)

What to do

The car drives normally. You may find the mirror will not fold, will not heat, or has stopped adjusting — or nothing obvious at all.

If a blind-spot warning has also stopped working, mention it, because the indicator for that system usually lives in the mirror and the two faults are typically one.

Say whether the mirror has ever been clipped or forced closed by hand. A folding mirror that has been knocked can report a position it is not in, and that is a different repair from an electrical fault.

The usual causes are cheap ones: the flexing wires in the rubber boot between door and body, or water reaching a connector inside a door whose drains have blocked.

What this code means

Mirror control module A is broadcasting data that cannot be accepted as true. See U0400 for what an invalid-data code is and why the module it names is usually the messenger rather than the culprit.

Almost everything in this range lives in a door, a seat or a tailgate, and that single fact is the most useful thing about it.

A door is the hardest place on a car to keep a wire alive. Every wire feeding a door module crosses from body to door through a rubber concertina — the harness boot — and that join flexes every single time the door opens. Ten thousand cycles later the copper inside a wire can be broken while its insulation looks perfect, which produces a fault that comes and goes with door position and tests fine with the door shut.

Then there is water. A door is a box with a window slot in the top and drain holes at the bottom, and it is meant to be wet inside. When those drains block with leaf litter, the water rises to where the module and its connectors live. Corrosion in a door connector is not exotic; it is the expected end state of a blocked drain nobody cleared.

So the order of work here inverts the usual advice. On this family the wiring genuinely is the first suspect rather than the last — not because invalid-data faults are usually wiring, but because this population of modules lives in the two wettest, most-flexed places on the vehicle.

Open the door and flex the boot while the fault is being watched on a scan tool. A reading that jumps when the concertina is squeezed has told you the answer in ten seconds, and it is the one test most likely to be skipped.

A door mirror stopped being a mirror some time ago, which is why it has a module at all. Folding motors, heating elements, position memory, puddle lamps, indicator repeaters, blind-spot indicators and increasingly a camera all live in that housing — and every one of those wires crosses the door harness boot described above.

The blind-spot function is the part that matters. Where the mirror carries the indicator for a side obstacle detection system, invalid data from it can take that system down with it — so a mirror code and a blind-spot warning appearing together are usually one fault, and the mirror is the place to look.

Physical damage is worth ruling out early and costs nothing. Mirrors get clipped in car parks and folded against posts, and a folding mechanism that has been forced can leave the position feedback reporting a place the mirror is not.

Likely causes

Start here

Broken wire in the door harness boot · moderate
Blocked door drain letting water into the module · easy
Water ingress into the module connector · moderate
Corroded or loose connector · easy

Less common

Damaged data bus wiring · moderate
Module not coded to the vehicle · specialist

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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