Parking Sensors

[nujon]

Today on starting the car, greeted with a continuous tone for several seconds plus flashing green LED on the PDC switch + no functioning PDCs - anyone recognise this fault and advise on solution please?

[dirtymonkey29]

Yup, you have a dead pdc sensor. You need to activate the pdc system then stick your ear next to each sensor. You should hear them clicking. The one not clicking is the knackered one. I have one out on the front so I disabled front sensors with BMW scanner 1.4.0 until I get around to swapping the sensor. It's a bumper off job on the facelift if it's a front one.

[pvw10]

The flashing tells you system fault (no sh*t) you just have to find which sensor has died and swap it.
Ignition on, in reverse and find a silent one. When you do try leaving it in a warm place overnight in case its soaked, worked for me once.

[nujon]

Thanks all - noted

I have checked the PDC system with a 1.4.0 scanner - some settings seemed haywire:-

1. turn on/off set to 'reverse rather than 'time/distance'
2. all audible PDC on/off signals 'on'
3. rear annunciator set to 'gong' rather than 'speaker' (its a speaker)

Have reset the above and cleared the fault codes and all seems to be working OK - had a flat battery today and had to jump start - maybe thats been the cause of the above? (or maybe wishful thinking on my part)

[nujon]

PDC problems have returned - sometimes they 'work' and sometimes they don't (green flashing light on switch + tone)

However, when they do 'work':

1. the system now activates on starting the car rather than engaging reverse

2. the annunciator tones sound different and distorted compared to previously

Anyone any ideas please?

[shadrack]

if you have bmw 1.4.0 or inpa it will tell u which sensor/s are knackerd and why

[nujon]

[quote=""shadrack""]if you have bmw 1.4.0 or inpa it will tell u which sensor/s are knackerd and why[/quote]

Thanks - do you know whether one faulty sensor can cause the whole system to go haywire - can't get my head round the distorted tones and the switch-on with ignition ?

[dirtymonkey29]

One faulty one will affect all. If its a front one you can disable front sensors with BMW scanner 1.4.0
Best way to find the dud is activate pdc system then go and listen to each one (put your ear real close) the one not clicking is the faulty one

[jaynana]

most of us have had faulty sensors. i had one faulty sensor once on the front.

any sensor gone means the whole system goes, ie, with one in the front gone the rears wouldnt work either, when reversing.

in anycase the symptom when a sensor gone are different to what you describe.

the symptom when a sensor gone is (if i remember well), when the system becomes activated (either when you put into reverse or manually activate with the button) it gives a long beep and the pdc green light keeps blinkin.

your symptom sounds different.

so where do u start - guess do what is said below, also i suggest you hook up a scanner and check what it says.

[x555]

You said in an earlier post that your battery was flat....this would be my first port of call as this can cause havoc with the x's electrics also your prob's sound different to most pdc's probs.

[dirtymonkey29]

After re-reading your post I would say it could be a dodgy battery or the pdc module. You can check the battery with a multimeter with ignition off, then with engine on and under load ie with lights, rear demist, heated seats etc. that will show potential alternator faults too. If battery is good I'd wanna get fault codes read. Maybe someone local to you has a scanner and can help you out for a few beer tokens.

[gadgetJunky72]

When i bought my X5 the PDC wasn't working at all. I got a continuous beep when going in reverse and the PDC button was flashing green. As has been mentioned the dealer assumed this was the normal problem of a faulty sensor. They diagnosed which one using the age old test of listening to each one.

When the faulty sensor was replaced the PDC started working but kept on beeping as if something was in the way. All the sensors were functioning so they then hooked the car up to a computer. It wasn't a BMW dealer so i guess they were using something similar to the 1.4 scanner. This helped them diagnose that another of the sensors was faulty and was giving false readings. I've been told replacing this second faulty sensor has now fixed the problem.