Central Electronics Failure

alexfwalker · Jan 21, 2023

Today my journey was interrupted by the dash lighting up with 'Central Electronics Failure'. I did a little Googling and that prompted me to pull out the plastic tray in the boot, on the driver's side. The tray was full of water, with two modules (I don't know what they are) totally submerged. In the photo below, you'll see that the green module is extensively corroded and I can't help but think that the CEF is related to the fact that quite a lot of electronics are submarining...

Note that the water is really quite clean, so I think this is rain water, not road water. However, I don't have a sun roof and no other part of the boot shows any sign of water ingress.

Two questions;

The space beneath this tray is probably designed to get some water in it, and then drain (I guess). Is that the case, and if so, where are the drain holes so that I can unblock them?
What are these two modules and can they be purchased and DIY replaced?

alexfwalker · Jan 21, 2023

Update - the green thing appears to be the module connected to the towing lights.

Johnnyroper · Jan 21, 2023

Yes green one is the tow bar bypass relay, grey one is the parking sensor module.

Johnnyroper · Jan 21, 2023

Oh and no it’s not designed to get water in there,it should be dry.
You need to find cause of ingress and sort it, boot seal,rear light seals,sunroof drains if sunroof fitted are some possibilities.
Bypass relay is a generic part that can be purchased online, the problem you have is the white plug will be part of tow at electrics so you will also need to source either the plug or new wiring. Speaking to a towbar fitter might be best to try and sort new parts. Wiring back to light circuit you should be able to get away with cutting corroded ends off and stripping back insulation to connect to new bypass.

nit sure if parking module would need coding to car if you got exactly same part number or if it would be plug and play.

Alan G · Jan 22, 2023

I would try drying them out and a good spray of wd-40 type spray.
Disconnect the battery for 20 to 30 minutes then test them again or just start the car and see what pops up.

alexfwalker · Jan 22, 2023

I’m intrigued as to whether the PDC is a plug and play unit. I can find hundreds on eBay, but all with a slightly different part number. Not sure if it’s actually a serial number.

Central Electronics Failure

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