gt2047 wrote:

Hi all, hopefully someone can help me with a bit of a mystery suspension fault…
I have a 2010 D4 that was suffering with the classic ‘normal height only’ suspension fault.
Long story short I replaced the desiccant / filters in the dryer and also rebuilt the front and mid valve blocks with new o-rings.

This got rid of the permanent suspension warning and the suspension works / adjusts through all levels, HOWEVER…. I am now in a situation where the suspension warning light comes on at random. Sometimes it comes on as soon as you start the vehicle, but then goes away after turning off / on. Sometimes I can use the truck and the light won’t come on at all - so it seems pretty random.

The front suspension drops when left overnight. I have thoroughly checked all air lines, unions, res tank and valve blocks for evidence of a leak using soapy water and all appears to be fine and air tight.
I have also inspected the looms behind inner arch splash guards and can’t see any damage anywhere there.

I have just done another overnight drop test, leaving the truck in off-road height and this time removing fuse 26 and to my surprise there appears to have been very little drop (a few mm maybe but I’m putting that down to natural settling).

Does this suggest that my fault lies within the ride level control module, or maybe a fault within the front valve block itself? is there something else I need to investigate?

Any help or advise would be greatly appreciated!
Cheers!

A largely irrelevant post without a fault code...

Once you have had the codes read, report back and we can advise further