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U0121

Code meaning and manufacturer information

U0121

What does this code mean?

The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.

A code identifies a detected condition, not a part that must automatically be replaced.

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A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.

Manufacturer communications

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Original wording in English

TSB 24-2117

FORD

Reported code forms U0121:87

Some 2024 F-150 non-Lightning vehicles equipped with minor feature codes C2BAW and FDDAA may exhibit an intermittent Trailer Brake System Fault See Manual message in the instrument panel cluster (IPC), inoperative…

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Check vehicle applicability

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A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.

MakeModelModel year
FordF-1502024

Historical records · 243 · Historical vehicle association; OBD-II compatibility is not established by this record.

Before replacing a part

Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.

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Can I keep driving?

A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.