Now and then when I reverse out of my garage the PDC system instead of bleeping front and back as it should just has a continous high pitch beep (the same tone as the front sensors).

When this happens it renders the system inactive and I get no further feedback on the car's proximity to anything front or back, which I'm finding really annoying.

Is this when the system is telling me there is a fault with one of the sensors?

Sadly it's becoming more often than not and I don't have the luxury of an OBD system to see what the fault code is and I certainly don't want to pay the dealer for 5 hours of faffing about.

Any ideas? Discovery 4 HSE
1998 110 TUM HS FFR Hard Top XD WOLF
1982 Series 3 Hard Top

*Gone:L462 D5 HSE LUX, L663 Defender 110 HSE, Discovery 3 HSE, 2014MY Range Rover Sport 5.0 Supercharged AB Dynamic; L405 Exec Vogue SE 4.4, 5.0 Supercharged Autobiography, Defender TDCi XS CSW, Defender TD5 HT, Vogue SE TDV8, Vogue TD6, RRSport SC 4.2V8, Classic 3.9 Vogue Auto, Land Rover Series 3 SWB

Are you certain there is nothing on the sensors? You haven't blasted them with a jetwash or anything recently? Checked for small children stuck to the bumper?

I got this from RAVE:

Diagnostics
The PDC ECU performs self check routines and checks the system wiring for short and open circuits. While the system is active the PDC ECU also monitors the data from the acoustic sensors.
If a fault is detected, a related fault code is stored in the non volatile memory of the PDC ECU and either the front sensors, the rear sensors or the complete system is disabled, as appropriate. To advise the driver of the failure, the PDC ECU flashes the indicator LED at 2 Hz and sounds a continuous warning tone for 3 seconds, in place of the normal short tone, when the system is activated.Fault codes can be accessed using TestBook/T4, which communicates with the PDC ECU via the instrument pack
and the I bus.

So basically the light should flash too if it's detected a fault.

Dan 

I have a RRS with a partially "melted" park sensor on the rear bumper (long story involving an Overfinch exhaust...), and whenever it rains or I wash the car the PDC system starts behaving like yours: 3 second high pitched tone from the rear buzzer as soon as I engage reverse, PDC button light flashing on the dash, both front and rear sensors inoperative until I restart the car or push the PDC button to extinguish the blink and reset the fault, but as soon as I engage reverse it starts all over again. After a few days - as the sensor dries out I guess, the fault no longer occurs. Don't know if this happens to you after the sensors get wet as well, but you could be having a similar issue if the problem seems to cure itself after a short while. You'll still need to hook up the car to diagnostics to identify which sensor is acting up, though.  Umberto B

Not long after I originally bought the car 2 years ago I found the PDC to be unpredictable and would often just beep away at nothing. As it was under warranty the dealer had it in 2 times but said there were no faults logged and they even dismantled it all, nothing bad found.


Do you BMW or Audi have these issues? Never.

There's nothing on the sensors and I don't use a jet wash on the car. Discovery 4 HSE
1998 110 TUM HS FFR Hard Top XD WOLF
1982 Series 3 Hard Top

*Gone:L462 D5 HSE LUX, L663 Defender 110 HSE, Discovery 3 HSE, 2014MY Range Rover Sport 5.0 Supercharged AB Dynamic; L405 Exec Vogue SE 4.4, 5.0 Supercharged Autobiography, Defender TDCi XS CSW, Defender TD5 HT, Vogue SE TDV8, Vogue TD6, RRSport SC 4.2V8, Classic 3.9 Vogue Auto, Land Rover Series 3 SWB

simple way to start diagnosing a pdc fault have a listen to the sensors. with the rr in reverse and put your ear close to each sensor you should be able to here a quite dit dit dit dit dit. when checking the sensors also check for a surdace damge to the head like scrapes or scuffs and if there is any paint lift on sensor. if a sensor is quite and not making any noise then remove the bumper and first inspect the bumper loom for damge or corrosion. if ok at this point i would say the sensor that was not doing the dit dit dit is at fault and would require replacing.

nathan

Love the "dit dit dit dit dit" sound efects - Great advise though

This fault stopped occurring not long afterwards, weird, it just went away and its normal ever since.  Discovery 4 HSE
1998 110 TUM HS FFR Hard Top XD WOLF
1982 Series 3 Hard Top

*Gone:L462 D5 HSE LUX, L663 Defender 110 HSE, Discovery 3 HSE, 2014MY Range Rover Sport 5.0 Supercharged AB Dynamic; L405 Exec Vogue SE 4.4, 5.0 Supercharged Autobiography, Defender TDCi XS CSW, Defender TD5 HT, Vogue SE TDV8, Vogue TD6, RRSport SC 4.2V8, Classic 3.9 Vogue Auto, Land Rover Series 3 SWB