Rover 75 Con Se CDTi Mk2 Tourer - Reverse parking sensors not working

[George2011]

Please can someone offer advise as my reverse parking sensors are driving me mad. I am a new member and have followed lots of advise from other threads on the same topic, but with no success.

My mk2 tourer has factory fitted reverse parking sensors which worked when I bought the car last summer. A few months ago they started working intermittently - sometimes fine and other times the dreaded 5 second beep. Now all I get is the 5 second beep. So from other threads I have done the following:

1. Checked each sensor for clicking - none of them click
2. Removed rear bumper and checked wiring assemblies and connections - they all seem fine, including the taped up assembly where the four black earth connections are joined together.
3. Checked the parking aid control box located above the drivers side wheel in the boot. I thought I had found the problem because the black connector, when removed was in a shocking state with water damage. So I replaced the control box and the black connector, checked the wiring to the connector 6 times but no - I still get the 5 second "system screwed" beep.

So I am at the point now where I am contemplating disconnecting it altogether but would really appreciate any advice. Have I missed something?

Thanks for any help you give

[Rov5]

Are your reverse lights working?

[George2011]

Yes, they have always worked and still do

[Jules]

Visual check is not good enough on the looms!
Do a continuity test between each pin.
You'll find some open circuit cables as the copper rots from water ingress.

The earlier 12 pin looms survive better than later 6 pin harnesses where MGR tried to save on wiring by using taped up joints ..................terrible .
Good job the never worked on aircraft.

I tend to rewire the whole bumper loom including new pin sockets available from RS.

BTW
There are 2 types of ECU black or grey and they are not interchangeable

Good luck

[George2011]

Thanks Jules, I had a fear you were going to say that. Hopefully the weekend might give me the time and weather to drop the bumper yet again and out with the multimeter!! I stripped the insulating tape from the join in the loom and all looked good and dry. The junction where the four black earth wires join four into one was shrouded in what looked like heat shrinked insulation, not simply electrical insulation tape and so I assumed (or hoped...), but we will see what the weekend brings.

I guess having found the ECU fault (and it was so bad one of the pins had actually detached, a continual sun roof drain seal leak) I was optimistic that two separate faults couldn't happen at the same time. Still this is just another step on what seems like a complete rebuild of my 75 from the tyres up.

As for the ECU, it was an exact replacement (albeit used from e-bay), both grey boxes with the same product numbers.

Thanks for the wise counsel.

[George2011]

At the weekend I finally got round to dropping the back bumper again to investigate the wiring behind. The wonderfully designed crimp holding all black earth connections together was as good as new when I stripped it down. No corrosion or even a hint of water ingress. So no further forward on a solution.

I then got to thinking about the broken control box (ECU) I replaced a few weeks ago. When it was replaced does the system need resetting?. Skimming through the Rover 75 body electrics manual, under the ECU replacement section it says that when replacing an ECU, the car needs to be reconfigured with a T4.

Does anyone have any knowledge of this? Will I need to take it to the garage or is there possibly a another fix? I kind of assumed that replacing the ECU would just be a straight replacement

[Jules]

No George
Parking ECU is plug and play.
No T4 involvement .

Did you do continuity checks of each wire to the sensor socket pins?

That's where there can be corrosion not just at the branch joins.

[mihaivolei]

i just payed yesterday at the garage £68 for this sensor

[Jules]

Including labour ?!

[Jules]

Wonder what the outcome of this was !!!