U045A: Invalid Data Received From Parking Assist Control Module A
What to do
Nothing about how the car drives is affected, and there is no safety consequence beyond losing an aid you may have got used to.
Check the free things first. Wipe every sensor in the bumper clean — mud, ice and packed snow are the commonest cause by a wide margin — and remove or look past anything fitted near them, like a towbar, a bike rack or a thick number plate surround.
Say whether the bumper has ever been resprayed or replaced. Paint over a sensor face is a genuine and very common cause, because the sensor has to be able to vibrate through a thin surface, and one extra coat is enough to stop it.
Notice which corner beeps. If the system sounds off constantly in reverse, that usually identifies the faulty sensor without any equipment at all.
What this code means
The parking assist module is reporting something that cannot be true. See U0400 for the family's framing.
This module reads a ring of ultrasonic sensors and passes on what they say, which puts it in the same position as the braking module at U0415: the value is wrong, and the module reporting it is usually working perfectly.
An ultrasonic sensor measures the time for its own chirp to come back. Anything that muffles the chirp, absorbs it or reflects it early makes the sensor report a distance that the others contradict — and the commonest causes are not electrical at all:
- Paint. A bumper resprayed with the sensors in place is the classic. The sensor face must be thin and clean, and one extra coat detunes it.
- Dirt, ice and packed snow, which is why these faults appear in winter and clear in a car wash.
- A towbar, bike rack, tow eye cover or number plate bracket inside the sensing cone, which the system reports as a permanent obstruction.
- Water in the sensor or its connector, since they sit at bumper height in road spray.
A stuck sensor announces itself audibly, and that is the free diagnostic. These systems normally chirp when they detect something; one sensor reading a permanent obstacle makes the system beep continuously the moment reverse is selected, or refuse to arm at all. Which corner it beeps for is usually which sensor is at fault, and pressing on each sensor face in turn while a helper listens will often identify it in a minute.
Nothing about the vehicle's driving is affected. This is a convenience system, and its failure is an inconvenience — the reason it is worth fixing is that a system crying wolf is a system the driver stops listening to.
Likely causes
Start here
- Corroded or loose connector · easy
- Water ingress into connector · easy
Less common
- Damaged wiring harness · moderate
- Physical damage from road debris · moderate
- Faulty receiving module input · specialist
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.
- What you measured, not only what you replaced.
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