U0433: Invalid Data Received From Front Distance Range Sensor — Single Sensor or Centre
What to do
The car drives normally, but adaptive cruise will not engage — and since this sensor usually feeds the automatic emergency braking too, assume the car will not brake for you.
Clean the sensor area first, because it is free and it is the commonest cause of this particular fault. The sensor is behind the grille, the badge or the lower bumper. Snow, ice, mud or a thick film of road salt does not stop it working — it makes it see things that are not there, which is exactly what this code describes. A wash often resolves it.
Then think about alignment. If the front of the car has been apart, or has had any knock at all — including a parking bump that left no mark — the sensor may be aimed slightly wrong, reporting real objects in the wrong places. It cannot be aimed by eye and needs the proper calibration procedure.
See P2583 for the fuller picture; this code, that one and U0235 describe the same sensor in three different states.
What this code means
The forward distance sensor is broadcasting data that cannot be accepted as true. This completes a set of three codes describing the same sensor from three angles, and knowing which one is stored genuinely directs the work.
- P2583 is a circuit fault the engine module reports about the sensor.
- U0235 is the sensor gone silent on the network.
- This code is the sensor talking and reporting distances that cannot be true.
That third case has its own distinctive causes, and they are the useful content here — because a radar that is reporting nonsense is usually a radar that is being confused rather than one that has broken.
Obstruction is the first, and it produces exactly this rather than silence. Snow, ice, mud or a heavy film of road salt over the sensor does not stop it working — it makes it see reflections that are not there, or fail to see things that are. The system detects that the readings do not make sense and rejects them. Cleaning the area resolves it, and it is free.
Misalignment is the second and is more insidious. A radar aimed slightly wrong reports real objects at wrong positions — a vehicle in the next lane placed in yours, or the one ahead placed off to the side. Those readings are internally plausible and externally wrong, and the system catches them when they contradict what the steering angle and wheel speeds imply.
Which is why the calibration question from P2583 matters here too: a bumper removed, a grille, a radiator, an accident repair however minor, or a parking knock that left no visible mark.
The safety consequence is unchanged and should be repeated: this sensor usually feeds automatic emergency braking as well as adaptive cruise. Assume neither is available.
Likely causes
Start here
- Radar sensor obstructed by dirt or snow · easy
- Radar sensor out of alignment · specialist
- Radar sensor not calibrated after front-end work · specialist
Less common
- Aftermarket fitting obstructing the radar sensor · easy
- Faulty front distance range sensor · specialist
- Corroded or loose connector · easy
Symptoms
Components involved
Information, not instruction
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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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- The car — make, model, year and engine. The same fault behaves differently on each.
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