[JordanM4]

Hi Guys,

I think this topic has been discussed a great deal over the years but just wanted to get clarification and see how many of you guys have had the issue.

On new years day I started my car after being rested for 2 days to this...


I then done a scan on INPA and got this


5E20 - HYDRAULIC PRESSURE SENSOR INTERNAL

Does this seem to be the Hydro unit fail and I need to purchase the following repair kit http://www.ebay.co.uk/itm/BMW-Genuin...item19e297ddf0 ?

Any ideas of cost of fitting etc?

[tmarshall57]

It does sound like your DSC Unit has failed. The part you need must match the part number of the part fitted to the car - there are numerous. The price for the module for 4 cylinder cars is around £200 whereas the price for 6 cylinder models is around £1,800.

It is possible that the fault is with the electronic module - not the mechanical module.

When I had this problem 12 months ago I removed the whole unit and sent it to ECU Testing who repaired for £250.00. Mine is a 6 cylinder model so this was a no brainer for me. Having the unit repaired also meant that there was no need to code a new unit to the car - which may be required if you replace the electronic module.

My story is here...

http://www.e90post.com/forums/showthread.php?t=813999

[JordanM4]

How did you go about refitting it, i dont get how you are supposed to bleed the dsc unit etc?

[a11y]

Only speaking from my experience (I had the same problem - I'm in tmarshall's thread linked above) but I didn't need to bleed the DSC unit.

Several guides I've seen online mention using INPA software to cycle the DSC pump. My unit arrived back from ECU testing filled with fluid. I reattached the brake lines (which I'd capped while the unit was off to minimise fluid loss - then bled the brakes as you normally would, i.e. at the bleed nipple on each caliper. In fact we bled them twice as they still felt a bit spongy after the first bleed so we re-bled them a week later - they're now perfect as is DSC/ABS function.

[tmarshall57]

I used the DIS 57 software. I didn't plug the ends of the brake hoses after removing the DSC unit. The theory is that, if you don't use INPA or DIS to "vibrate" the ABS valves, then some air bubbles are likely to stick to the walls of the ABC unit causing spongy braking. Personally I think you can get around this by bleeding twice as A11Y has suggested, taking the car on a gravel path and triggering the ABS between bleeds.

[a11y]

Originally Posted by tmarshall57

I used the DIS 57 software. I didn't plug the ends of the brake hoses after removing the DSC unit. The theory is that, if you don't use INPA or DIS to "vibrate" the ABS valves, then some air bubbles are likely to stick to the walls of the ABC unit causing spongy braking. Personally I think you can get around this by bleeding twice as A11Y has suggested, taking the car on a gravel path and triggering the ABS between bleeds.

Yup, my thoughts are my spongy braking was due to not bleeding the DSC unit as recommended (no matter how careful I was capping the ends, some air would still have got in). I covered approx 200 miles in that week between the first and second bleed and ensured I gave the ABS a good workout on a slippy surface. Only my thoughts though, might be wrong!