Disco 2 ACE Problem

Gros Niglik · Friday at 17:35

I plugged in the replacement ACE ECU today. The only difference was that there is now a reading of 000.01 amps and both DCV1 and DCV2. With the old ECU the value was 000.00 amps. All the other values were within the same range as each other. The same was true when I removed the relay and bridged the contacts. However, with the bridged relay contacts the warning light appeared on the instrunebt board. There was also a fault dispayed: FAULT 20-04 - PRESSURE CONTROL VALVE FAULT. This only appeared when the relay was bridged.
I tried the outputs which did not activate the warning light.
I have not yet tried the car on the road.

sierrafery · Friday at 18:24

You should have road tested it before diagnosing cos it's possible that the ECU had a hystorical fault logged.... the outputs should work only with relay in it's place... erase the codes and road test it then we'll speak

Gros Niglik · Friday at 19:36

Thanks for the commentary. I will roadtest tomorrow.

Gros Niglik · Saturday at 19:55

I road tested and I am still getting the amber warning light once I reach about 20 km/hr. Another surprise is that the 3 amigos appeared. I had previously solved that problem by changing the ABS shuttle valve. I don't think it is related to the ACE.

I have asked previously do you think it possible that I damaged the ACE pump when the feed and return pipes were connected in reverse to the valve block? There appears to be a lot of pressure on the pump discharge because it spurts considerably when the banjo bolt on the pump is slackened. There is not the same degree of movement in the resrvoir as in the PAS reservoir.

Next step to change valve block for the new (used) unit that I just purchased?

sierrafery · Saturday at 20:08

Gros Niglik said:
I have asked previously do you think it possible that I damaged the ACE pump when the feed and return pipes were connected in reverse to the valve block?

I don't really think the pump was damaged albeit not impossible but as discussed in post #14 it's possible that the attenuator was somehow hurt and now it restricts the flow, unfortunately i don't khow how that feed pipe was built... i hope you erased the code before the drive test and if yes what's the new code now?

Gros Niglik said:
I am still getting the amber warning light once I reach about 20 km/hr.

Did it behave the same before the ECU swap too or it was permannent red warning then or how? ... also that 20km/hr thing means that the warning goes out after the self check and comes on just at that speed?

if the warning lamp goes out after the self test what are the pressure readings then?(no need to bypass the relay if the lamp is off)

wait with the valve block for now untill it's not clear enough what's going on

Gros Niglik · Saturday at 20:18

It behaves the same as before the ECU swap. THe light is amber and sometimes red with sound alarm when I turn sharply from a standstill. With the new ECU, as metioned previously, the DCV's show a value of 000.01 whereas before it was zero. When the outputs on the Nanacom such as the warning light and the DCV's nothing happens.

What makes me suspect the high presure attenuator is that there is high pressure at the pump but not much agitation in the reservoir. perhaps the attenuator restricts the flow. Why would there not be much movement in the reservoir?

sierrafery · Saturday at 20:36

Gros Niglik said:
It behaves the same as before the ECU swap. THe light is amber and sometimes red with sound alarm when I turn sharply from a standstill. With the new ECU, as metioned previously, the DCV's show a value of 000.01 whereas before it was zero. When the outputs on the Nanacom such as the warning light and the DCV's nothing happens.

What makes me suspect the high presure attenuator is that there is high pressure at the pump but not much agitation in the reservoir. perhaps the attenuator restricts the flow. Why would there not be much movement in the reservoir?

Have patience untill monday then i'll make some tests with nanocom on mine to see how it behaves with a 100% working system cos i dont have much confidence in it when it comes to ACE, i'm asking again: ... that 20km/hr thing means that the warning goes out after the self check and comes on just at that speed?...or it's permanently on?

Gros Niglik · 2025-01-26T00:45:38+0000

The amber light illuminates when I reach approximately 20 Km/hr. If I turn the ignition off, the amber light ( or in the case that the red light illuminates) the light is not present. BTW, I appreciate the tome you have taken to help me.

sierrafery · 2025-01-26T07:34:50+0000

Gros Niglik said:
The amber light illuminates when I reach approximately 20 Km/hr. If I turn the ignition off, the amber light ( or in the case that the red light illuminates) the light is not present. BTW, I appreciate the tome you have taken to help me.

That means that the system passes the initial self test hence the good idle readings and it detects low pressure while driving ... did you take extreme care to not let any dirt into the block when you changed it?

btw, what's the fault code now?

Gros Niglik · 2025-01-26T16:06:32+0000

I could have done a better job of keeping dirt out of the system when I changed the valve block. I changed the filter but as mentioned previously, when I checked it a few days ago there was quite a lot of debris on the filter.

The current fault codes are as follows: FAULT 18-04 Hydraulic or mechanical fault in the pressure control system.
and FAULT 20-04 Pressure control valve fault.

If the the attenuator in the high pressure pipe is causing a restriction, would this cause the displayed faults?
BTW, the pressure transducer and the blue pressure control valve solenoid are new.

Stanleysteamer · 2025-01-26T16:49:58+0000

Gros Niglik said:
THe light is amber and sometimes red with sound alarm when I turn sharply from a standstill.

Could this in any way possibly be an indication of a problem in the harness where the dreaded P-clip causes trouble?

Gros Niglik · 2025-01-26T16:56:29+0000

What is the dreaded P-clip? Is this the connector adjacent the fuse box?

Stanleysteamer · 2025-01-26T17:15:39+0000

Gros Niglik said:
What is the dreaded P-clip? Is this the connector adjacent the fuse box?

No, it is on top of the transfer box I believe but it induces wear in the insulation in important cables which is invisible often until the wretched thing is taken off and examined in great detail.
The reason I am hesitant about this and waiting for @sierrafery to comment, is that he probably knows whether or not this could be a link to your issue.
Is was just the fact that you said that something happened when you turned sharply from standstill. Movement of the vehicle in certain ways has been known to exacerbate this problem but on the other hand could be an indicator of it.
At least it might be worth looking into. If it is that it is a very easy fix.
There are threads about this on here, I will wait until someone comes on and comments and hopefully puts up a link, if it could be the problem.
But you do seem to be getting to the end of normal issues with your problem.

Gros Niglik · 2025-01-26T17:52:45+0000

Thanks for your comments. I will have a look when I get Hank (that's his name according to the previous owner- Hank the Tank) back up on the lift.

sierrafery · 2025-01-26T20:42:08+0000

The P clip has nothing to do with the ACE, as the system passes the self test and the warning appears only when the ACE becomes active(at around 20km/h) and considering that the codes are correct + weak fluid activity IMO the problem is most probably hydraulical. The system is very sensitive to dirt or something bad happened in the valve block when the pipes were connected the other way around also it's possible to be air in the system too. You should drive it as fast as you can with many cornerings both ways to force air out if it's there cos i doubt that nanocom would complete a purging sequence. At this point i'd incline to tell you to replace the block too if you have a spare to be ruled out just blow it well with compressed air through all the holes first and work with extreme care to not let dirt in.

Stanleysteamer · 2025-01-26T20:56:33+0000

sierrafery said:
The P clip has nothing to do with the ACE, as the system passes the self test and the warning appears only when the ACE becomes active(at around 20km/h) and considering that the codes are correct + weak fluid activity IMO the problem is most probably hydraulical. The system is very sensitive to dirt or something bad happened in the valve block when the pipes were connected the other way around also it's possible to be air in the system too. You should drive it as fast as you can with many cornerings both ways to force air out if it's there cos i doubt that nanocom would complete a purging sequence. At this point i'd incline to tell you to replace the block too if you have a spare to be ruled out just blow it well with compressed air through all the holes first and work with extreme care to not let dirt in.

View attachment 333950

Thanks for clarifying.
I do wonder if anyone could sort out the things the P-clip can affect, as opposed to those it can't.

Gros Niglik · 2025-01-26T23:01:22+0000

I bought a valve block from the same supplier from which I bought the ACE ECU, It is verry clean and looks to be in excellent condition. Before I change the valve block entirely, I will try another pressure regulating valve. I will also check the high pressure pipe to see if there are any restictions.

sierrafery · 2025-01-27T10:43:49+0000

So, tested nanocom on mine, the values at idle from cold start are as in the pic with slight fluctuations(there are moments when some silly values are displayed for a second but that's certainly a glitch), on the DCV's the values were 0.000 at first then i checked again after the output tests and they were 0.001(not relevant IMO)... sorry for the quality it
was sunny outside but you can see if you magnify it.

The warning lamp starts flashing on Output - ON command and stops with OFF, for the DCV test - ON extreme attention is needed but you must feel a short movement in the body once then OFF on that valve and go to to the other which must behave the same... just be aware that it's a very weak movement but if you expect to feel it it's certainly there, try more times on both valves consecutively with on-off as i explained... or get assistance, my son kept his hand on the DCVs and he noticed some activity

see the video(it expires in 24 hours) how the fluid's activity must be:

IMO if your ACE fluid is not pretty the same with the PAS your problem is definitely with the pressure for some reason(i dont know why yet, might be as simple as dirt in the block)

meego · 2025-01-27T11:04:32+0000

All of the above adds up to a perfect reason for bypassing the ACE system. And before anyone jumps down my throat….yes, it’s an excellent system that works extremely well……when it works !!!!
This does depend on where you are in the world of course, and the condition of the pipes and actuators etc. Somewhere hot and dry, then salt water corrosion may not be a problem like where I am. But as a D2 owner who bypassed the system quite a few years ago with no real issues, it’s a no brainer for me.

Disco 2 ACE Problem

Member

Well-Known Member

Member

Member

Well-Known Member

Member

Well-Known Member

Member

Well-Known Member

Member

Well-Known Member

Member

Well-Known Member

Member

Well-Known Member

Well-Known Member

Member

Well-Known Member

Attachments

Well-Known Member

Similar threads