Disco 2 ACE Problem

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Gros Niglik

Member
Posts
16
Location
Montreal
The amber light and sometimes the red light illuminates. The system worked fine until I changed all the hydraulic lines. I also changed the valve block for a used one because one of the connection points was damaged on the original. The pressure transducer, the blue pressure control valve solenoid and the front actuator were also replaced. I also tried swapping the mecanical components from the original valve block.

I should report that I made an error by inadvertantly swithing the position of the bottom two hydraulic lines on reassembly. I was concerned that I might have damaged the pump. The pump is new and squirts lustily when the banjo bolt is loosened. Could the attenuator in the hydraulic line from the pump been damaged or jammed?

I used a NANOCOM to bleed the system and even took it to the local Land Rover dealer to service. They told me that they bled the system but the last function in the procedure (whatever that was) didn't work. They said there was a mechanical fault in the valve block.

With my NANOCOM I get two (2) faults: FAULT (1): 18-04 Hydraulic or mechanical fault in pressure control system. and Fault (2): 20-04 Pressurure control valve fault.
Needless to say, the hydraulic fluid was changed several times along with the filter. THere is circulation in the reservoir but nothing like the level of circulation in the PAS reservoir.
I have been fighting this problem for months with no joy.

Any ideas? Do I try another valve block? Could the SLAB be faulty?
 
With my NANOCOM I get two (2) faults: FAULT (1): 18-04 Hydraulic or mechanical fault in pressure control system. and Fault (2): 20-04 Pressurure control valve fault.
Needless to say, the hydraulic fluid was changed several times along with the filter. THere is circulation in the reservoir but nothing like the level of circulation in the PAS reservoir.
I have been fighting this problem for months with no joy.

Any ideas? Do I try another valve block? Could the SLAB be faulty?
First of all the SLABS has nothing to do with the ACE which has it's own ECU near the SLABS, nanocom used to give false codes when it comes to ACE so you can't rely on the codes only, you should find somebody with hawkeye or for nanocom remove the ACE relay, bridge the contact cavities in the fusebox with a wire, read live inputs at idle with bridged relay and report the values then i'll tell you more.
 
First of all the SLABS has nothing to do with the ACE which has it's own ECU near the SLABS, nanocom used to give false codes when it comes to ACE so you can't rely on the codes only, you should find somebody with hawkeye or for nanocom remove the ACE relay, bridge the contact cavities in the fusebox with a wire, read live inputs at idle with bridged relay and report the values then i'll tell you more.
I actually did introduce myself some time ago. I am in Montreal and have done extensive work on this Discovery 2. The suspension has been completely rebuilt including all bushings, nalljoints springs shock towers, shock absorbers, wheel bearings, all steering components, differential seals, brake rotors and calipers, PAS pies and pump etc. I have been mucking about with cars since I was 15 years old (I am now 74 years old) starting with a slew of Austin Minis. I just finished a ground up rotisserie restoration of a 1965 E Type. Is there anything else you wish to know? I am stumped on the ACE issue. Hopelully you have some suggestions.
 
BTW the report from the dealer said that the problen was that the syestem needed bleeding. That is when I bought the NANOCOM. I went through the bleed procedure but never had the feeling that it did anything. I then paid a ludicrous amount of money for the dealer to bleed the system. Their diagnostic system said that there was an internal failure in the vakve block. Doesn;t make sense to me since the pressure transducer, the blue solenoid are new and the other two solenods tested alright and they woked befor I changed the hydraulic pipes. I will get to the relay jump as soon as I am able. Cheers.
 
BTW the report from the dealer said that the problen was that the syestem needed bleeding. That is when I bought the NANOCOM. I went through the bleed procedure but never had the feeling that it did anything. I then paid a ludicrous amount of money for the dealer to bleed the system. Their diagnostic system said that there was an internal failure in the vakve block. Doesn;t make sense to me since the pressure transducer, the blue solenoid are new and the other two solenods tested alright and they woked befor I changed the hydraulic pipes. I will get to the relay jump as soon as I am able. Cheers.
 
BTW the report from the dealer said that the problen was that the syestem needed bleeding.
IMO main dealers know nothing these days about how the systems on these old vehicles are working, not much about the newer ones either other than changing the filters and oils in warranty... all they want is to sell vehicles and dont give a sh*t about fixing them cos once you paid big money they should have not sent you away with a silly explanation just like that,
Their diagnostic system said that there was an internal failure in the vakve block.
i can't imagine what the heck can fail or communicate with diagnostics within a valve block as to give that result, it's a block of alloy with holes and channels inside for the fluid, nothing electrical nor mechanical, all the working parts(solenoid valves and sensor) are fitted from outside so the diagnostic tool can't know what's inside...unless the valve itself it's stuck, the DCV's can be triggered with nanocom in outputs to hear them clicking but the PCV is not covered by that function, you could give direct 12V to it and see if it's clicking or not.

btw did you replace or at least clean the filter too? cos the fluid in the tank should move at least the same like the PAS
 
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Yes. I changed the filter for a new one. The motion in the reservoir is nowhere near the motion in the PAS reservoir. Thanks for that information. Do you think that when I I switched the two bottom hydraulic lines by mistake on reassembly the attenuator in the pipe from the pump got jammed and restricts the flow?
 
Yes. I changed the filter for a new one. The motion in the reservoir is nowhere near the motion in the PAS reservoir. Thanks for that information. Do you think that when I I switched the two bottom hydraulic lines by mistake on reassembly the attenuator in the pipe from the pump got jammed and restricts the flow?
I don't think so but possible as it got backflow then albeit i dont really know how that attenuator works... we'll know more when you tell the live pressure inputs
 
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I put a jumper in place of the relay and got the following results:

Engine speed: 750rpm
Battery voltage: 14.28V
DCV1 (amp): 000.0
DCV2 (amp): 000.0
Pressure control valve (amp): 000.13
Pressure sensor (bar): 016.11
Residual pressure (bar): 003.88
Upper lat acc: 000.00
Lower lat accc: 000.20

Are DCV1 and DCV2 supposed to indicate 000.0?
 
The pressure values are looking OK, as about the DCVs i think it should not be zero but at least 0.01... i don't know if nanocom is 100% reliable with this, i have hawkeye too and when it comes to ACE i'm using only that one but i'll check with nanocom on mine tonight to compare ... go to outputs with bridged relay first and check if the DCVs are clicking on command also see if the warning lamp flashes on test then put the relay back and check again(the relay too this time) then report the result cos at this point the ACE ECU is a bit suspect

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I did as you suggested, bridged the relay #R14, and tried the outputs and nothing happened when I pushed the "on" button on the NANOCOM screen for the diectional valves or the warning light. I assume this is waht I am supposed to do for the test. I did verify that power was at the relay and also that the relay was functioning. I also checked the contacts of the plug adjacent to the fuse box and everything was clean and corrosion free. I will check the connections on the ECU as soon as I am able. If the connections are good it sounds like the ECU itself is suspect. It is curious because the system worked fine before I changed the hydraulic lines. Life was so much easier before the advent of electronic this and that. The electrical diagram for my E type is one (1) page. Your help is much appreciated.
 
I did the test yesterday with the relay installed as you suggested with the same result. Nothing happened when I pushed the on button for the light or any action from the valve block solenoids. The relay functioned in the horn slot (R15) and I checked the operation of the relay itself. I also checked to ensure that there was power to the relay (terminal 3 and terminal1).
Any more comment regarding "0" volts on DCV1 and DCV2?
 
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