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Diagnostic trouble code

U1A00

0 owner reports and 31 manufacturer filings across 16 model years from Ford, Lincoln.

NetworkManufacturer-specific31 manufacturer filings

Where U1A00 shows up

Source: NHTSA manufacturer communications and complaints
Model yearFiled underBulletinsOwner reports
2016 Ford FocusEngine And Engine Cooling3
2016 Ford C-MAXEquipment2
2024 Ford EscapeUnknown Or Other2
2016 Ford ExpeditionEquipment2
2024 Ford F-150Electrical System2
2016 Ford FiestaEquipment2
2016 Ford FlexEquipment2
2016 Ford MustangEquipment2
2016 Ford TaurusEquipment2
2024 Lincoln CorsairElectrical System2
2016 Lincoln MKCEquipment2
2016 Lincoln MKSEquipment2
2016 Lincoln MKTEquipment2
2016 Lincoln NavigatorEquipment2
2017 Ford Transit ConnectEngine And Engine Cooling1
2023 Lincoln CorsairEquipment1

A model year appears here because the code is named in its record, not because every one of these vehicles sets it. Counts are mentions in the federal files, not failure rates — nobody publishes the denominator.

What it gets filed under

Equipment 12Electrical System 8Engine And Engine Cooling 7Unknown Or Other 4
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Manufacturer filings that name it

Source: NHTSA manufacturer communications

Service bulletins and campaigns whose filed summary names U1A00. Quoting the document number at a service desk is often the fastest route to a diagnosis someone has already written down.

What U1A00 means

Source: SAE J2012 / OBD-II

U1A00 is a manufacturer-specific code: the second character is a 1, which under the OBD-II standard hands the definition to whoever built the vehicle. The same code can mean one thing on a Ford and something unrelated on a Hyundai. Any site that prints a single definition for it is guessing.

A stored code names the test that failed, never the part that caused it. It is the starting point of a diagnosis, not its conclusion — the same code has several possible causes and the cheap one is not always right.

Common questions about U1A00

Source: NHTSA files and the OBD-II standard

Why does this page not define U1A00?

Because it cannot be defined honestly. The second character of a trouble code says who owns its meaning, and a 1 or a 3 hands that to the manufacturer. Sites that print one definition for a manufacturer-specific code are showing you one automaker's meaning and hoping it is yours.

Can I keep driving with U1A00 stored?

Nobody can answer that from the code alone, and a site that does is guessing. A steady light generally means the fault was logged and the vehicle is in a reduced-risk mode; a flashing light means stop soon, because a misfiring engine can destroy a catalytic converter in minutes. The safe read of this page is the mileage and the components, not permission.

Does a code mean the car is recalled?

No. Recalls are filed by campaign and matched by VIN, and none of them are triggered by a scan tool. If you want to know whether an open recall applies to one specific vehicle, check the VIN at nhtsa.gov/recalls — that is the only source that settles it.

Why do the counts here differ from other sites?

Because these are not estimates. Every number on this page is a count of documents in NHTSA's own files: manufacturer communications that name the code in their filed summary, and owner complaints that name it in the narrative. We do not model, weight or extrapolate them.

Will clearing the code fix it?

Clearing turns the light off and erases the freeze-frame data a technician would have used to work out what happened. If the condition is still there the code returns, usually within a few drive cycles, and the diagnosis now starts from less information than before.