Rear parking sensors have a mind of thier own

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Rear parking sensors have a mind of thier own

Postby Exile » Thu Jun 28, 2012 11:25 am

Has anyone had a problem with rear parking sensors working intermittently?
My 54 reg 2.0 diesel saloon has developed the habit of emitting a continuous beep, i.e. sensor occluded, at random times when reverse gear is engaged. This happens when the sensor area is free of obstructions, and is apparently random. Re-engaging reverse gear will sometimes clear the fault. All four sensors were replaced by main dealer when I pruchased the car in December 2006. Although not life threatening, this is BEEP annoying.
Any help/advice gratefully recieved.

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Re: Rear parking sensors have a mind of thier own

Postby J44EAG » Thu Jun 28, 2012 1:31 pm

I`ve had this on S-types.

It was a flooded module in the boot wheel well. Replacement cured the problem. However, occasionally the issue still surfaces but on my S, repeated selection of reverse and switching the ignition on and off eventually returns normality.

You might try opening up the module box and checking for corrosion. It is worth attempting to clean up if corrosion is present on the pc board because at that point you have nothing to loose. Also clean the module plug pins and the multiplug. You might be lucky.

If you need to replace the module, consider second hand to save cash. Only replace with the exact part number on the module case. Any other part number is unlikely to work.

Check to see the sensors are clean especially between the sensor itself and the outer mounting ring.

Sorry I can`t be more helpful. May be someone else has a more definitive answer.

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Re: Rear parking sensors have a mind of thier own

Postby Montana5 » Thu Jun 28, 2012 4:58 pm

Copy of my post on the S Type section...

If I can add a little to this. One of my sensors has the paint blistered and gives off a sometimes continuous and other times broken bleep, I have still to get round to re painting it, however it was explained to me that the ultrasonic jet (if that is the right term) is bouncing off the blown paint and causing the spurious bleeps.
Some other tips I picked up along the way...

Sometimes the gap in the Sensor rings get filled with dirt, if you can clean this with a soft brush it might help.

Each Sensor should emit a ticking sound when in reverse, go round each one listening for this, if one is not making the sound it could be that Sensor is at fault.

I have read that the two outer Sensors are accessible within the boot, by removing the rear light clusters.

Someone did have the problem solved by remaking a dirty wiring pin connection to the Module (Car loom side) he reckoned it was caused when water got into the Boot.

I read recently on another forum, about an S Type Owner who bought a new Sensor from E-Bay (£20.00) and swapped it with each Sensor, one at a time to, find which was faulty, luckily he started with the two outer Sensors and found it was the second one.

Hope some of this helps, let us know how you get on.


ps. I had my blistered one repainted two weeks ago and all is hunky dory again.
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Re: Rear parking sensors have a mind of thier own

Postby andypryce » Thu Jun 28, 2012 8:34 pm

I would agree with both possibilities, had a faulty sensor on my S type, if there is a fault when you engage reverse you get a continuous beep for about 3 seconds, then nothing, as the system shuts down. If the beep is continuing then I guess a sensor is misreading the distance, which might be down to the paint issue. It is very hard to hear the ticking, but if you engage reverse and place a finger gently over each sensor you can just feel the pulsing, rather than trying to hear it. and yes you can get new replacements on ebay, paint them up and fit (not an easy job on an S Type), much cheaper then letting a dealer do it. I am guessing of course that the X Type is the same.....

Hope that helps,


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