E46 Parking Sensors Problem

[Progressive]

My parking sensors on my E46 have worked perfectly for the past 18 months. Recently they have started playing up.

Sometimes they work without an issue. At other times they will 'jam on' so the warning tone is constnt. Sometimes after engaging reverse 2 or 3 times, they start functioning correctly.

I'm stumped as to what it can be as they have proved that they do actually work, just not all the time.

Any advice on how to reset them (I'm thinking there might be a similar reset function to E46 windows / sunroof). Otherwise, any suggestions on a fix?

Thanks,

Progressive

[Slurms]

Unfortunatly this is a common problem

I've never heard of anyone being able to reset them but they can be removed and replaced if they have developed faults.

[stevesuk]

Mine started working intermittently, and then not at all (the long beep when you engage reverse).

It was a fault in the wiring that I managed to sort myself. Basically, one of the wires had a break in it as it entered the back of the plug on one of the sensors. Blob of solder and some insulation tape, and they've been fine since (touch wood!).

Wondered if a squirrel or some other animal had bitten through it, or whether a stone had been flicked up under the bumper at motorway speeds.

[bmwtechie]

next6 time it goes onto a constant tone, then put ur ear up to each sensor in turn and u should hear a quiet clicking sound from each one, the one not clicking is faulty and needs replacing, if none of them are clicking chances a re its a control unit fault, but it does sound more like one sensor has gone down, and its common for it to work intermittently

[Speed addicted]

I recently replaced one of the sensors on the back of my X5 after getting the long tone then nothing (and having a near miss with reversing into the garage door).
If a sensor is faulty it is easy to find the duff one when they don't click/or make any noise.
Then it's a mere £75 for a new one...

[LeightonBuzzard]

bmwtechie said:

next6 time it goes onto a constant tone, then put ur ear up to each sensor in turn and u should hear a quiet clicking sound from each one, the one not clicking is faulty and needs replacing, if none of them are clicking chances a re its a control unit fault, but it does sound more like one sensor has gone down, and its common for it to work intermittently

I've got this problem with mine, ill give it a go, cheers

[NickXX]

Speed addicted said:

I recently replaced one of the sensors on the back of my X5 after getting the long tone then nothing (and having a near miss with reversing into the garage door).
If a sensor is faulty it is easy to find the duff one when they don't click/or make any noise.
Then it's a mere £75 for a new one...

They're a tad cheaper for the e46 as they're unpainted. I picked one up for £20 on eBay.

As mentioned above, stick the key in position 2 (don't start the car) and select reverse. Then listen to the ticking on each of the sensors.