W212 Parktronic failure

[Tym]

Hi peeps. Newbie here so go gentle on me!

Used to have a 1991 E230 years ago, and now I've just replaced my old Saab 9-3 TTiD (which had 213k on the clock) with an 61 plate E220 CDI. Lovely car, and nice to be back behind the three point star again.

However... whilst everything has been working fine, the day I put my cherished number on, the parking sensors stopped working. Used to be perfect, but now the bypass switch on the dashboard is permanently red.

I've bought an MB2 from Diagnostic World, and that gives me a fault code of A12500 with the message "The power supply of the sensors us outside the valid range". Checked fuse 80 and that's fine.

Interesting to note that the module says it's on, but the bypass LED is lit. Pressing the bypass *does* turn the module on and off, but no effect on the red LED.

Seems odd that this only happened when I changed the number plate, with standard length number plate screws...

Anybody seen any fault codes starting with A before, and where should I start looking?

Thanks...

Tym

 

[Blobcat]

Hello and welcome

I’d be checking behind the bumper that you’ve not caught a wire

 

[Tym]

Thanks Blobcat,

That's where my train of thought was going, but I was hoping not to have to peel the front bumper off quite so soon after buying it.

I presume that's the only way to make room to get to the sensor?

Its strange that all I did was unscrew the two screws from the old number plate, and put two new screws back in. The sensor wires must be in a stupid place if they can be interfered with by a standard length number plate screw.

I find it odd that it gives this error rather than a faulty sensor...

 

[Tym]

Hello and welcome

I’d be checking behind the bumper that you’ve not caught a wire

Well, nice sunny day so decided to peel off the bumper...

Turns out the number plate screws (both of them) has both gone through the wiring loom. Luckily they hadn’t severed any cables and once I re-bound the loom everything was fully working again. Ironically, if I’d just taken the screws out and shortened them, the problem would have been absolved without the need to take the bumper off, but there to go!

All working again!