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ACE Valve Unit Failure

Hi Greenmonster,
When you have had problems with ACE, Do you remember if your old ACE ECU reported a fault code related with the Directional Control Valve?
 
Hi Cesar,
I don't recall a fault code realting to the Directional Control Valve. If the problem on your car is this I believe they can be replaced, rather than the whole ACE block.

The results from my diagnostic tests were this with engine running at idle and car stationary:

reverse switch not reverse
main relay off
warning lamp on
engine speed 720rpm
road speed 0
upper lateral accl - 1.43g
lower lateral accl -1.43g
direct ctl valve 1 = 0.01amps
direct ctrl valve 2 = 0.01amps
battery volts 0.03volts
press ctrl valve 0.02amps
press sensor 0 bar
residual pressure 20bar
system pressure 0 bar
ignition swtich on

I've found a replacement ACE ECU which should fit your car. The part number is RQT100030 - this is one of the later versions, check your part number against it.

http://www.ebay.co.uk/itm/Land-Rover-Discovery-2-Td5-and-V8-ACE-ECU-part-number-RQT100030-/140913909930?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item20cf1fa0aa

works out about 14,200 peso compared with some on ebay.com that are over 27,000 peso
 
The ACE ECU of my Discovery 2 is te same (RQT000030) but, the seller didn't ship to Chile :(
I was reading the D2 Workshop Manual and I found that the DCVs are not serviceables, and if they fault, they can't be replaced and the solution is replace the whole ACE block :(
I will try to replace the DCVs O-rings, the ACE ECU and the hydraulic fluid, and I hope fix the problem with this changes. If you know somebody who have fixed or replaced the DCVs, please tell me.
 
Somebody know if the ACE pump can be fixed? I ask this because now I only have problems with this DTC:

DTC: 41 The system pressure has been below a threshold for a time, when a pressure has benn demanded. Logged fault.

And, the ACE pump is a little bit noisy...
 
The pressure transducer that sends the signal to the SLABS ECU is a known problem area. I'd look at what is coming out of that before changing the pump.

Peter
 
I have replaced the ACE transducer and the problem don't disappear, also I changed the ACE hydraulic fluid and the ACE filter, I put Land Rover PAS Cold Climate STC50515. Next week I'm going to replace the ACE ECU but I think the problem could be the ACE pump because is too noisy. This is the reason because I ask if this pump could be serviceable.
 
There are no known pump service kits, new pumps are on ebay for £300+ or used ones for £50 - £100, all plus postage.

I don't know of another vehicle using this system either.

Peter
 
Last week I replaced the ACE ECU and after to drive 200 km on traffic jams, apparently the problem went away but, now I have another problem... Yesterday I was trying to calibrate the accelerometers with my Hawkeye because, when the vehicle is parked on a level floor, the upper accelerometer read -0.02g and the lower accelerometer read -0.03g, but according with the "LUCAS ACE -System Overview", both accelerometers should read -0.01g on a level floor.
After to try many times to calibrate the accelerometers, the result was always the same, -0.02g upper and -0.03 lower. So I don't know if the problem is with accelerometers or with the Hawkeye (V5.0).
Somebody know what could be the problem?

Regards!
 
I'd like to resurrect this old thread as it has helped me a lot so far and is near the top of google searches for ACE amber lights problems.

I am having the same problem with the same data read from a hawkeye as greenmonster on page 4.

My amber ACE light came on and I got these error codes:
DTC 22 Pressuresignal out of range.
DTC 23 Invalidpressure signal received.
DTC 42 Thecalculated temperature has exceeded a threshold for a time.
DTC 45 The PCVcurrent has been below a threshold for a time, when a current hasbeen demanded. [Note PCV = Pressure Control Valve]

Reading from the Hawkeye are:
Upperlateral acc -1.43 G
Lowerlateral acc -1.43 G


DirectCtl Valve1 0.01 Amps
DirectCtl Valve2 0.00 Amps


Batteryvoltage 0.03 Amps
PressureCntrl Valve 0.00 Amps
Pressuresensor 0.00 bar
ResidualPressure 20.00 bar
Systempressure 0.00 bar


Ignition switch ON
Pressure switch ip Not reverse
Main relay OFF

I cleared the DTCs and ran the haweye's system test: with these results:
pressure sensor 0.00 bar
Residual pressure @ 5.2 bar. (don't understand how this is now not 20 bar?)


Direction valve 1 1020 ms ON time (should be 15-60ms)
Direction valve 1 20 ms OFF time (should be 15-60ms)
Direction valve1 1020 ms SYSTEM time (should be 100-250ms)


Direction valve2 1020 ms ON (should be 15-60ms)
Direction valve 2 32 ms OFF time (should be 15-60ms)
Direction valve2 1020 ms SYSTEM time (should be 100-250ms)


Pressure valve 1020ms ON time (should be 4-50ms)
Pressure valve 1020ms SYSTEM time (should be 0-90ms)

DTCs that returned after the test were just the DTC 45. After driving the others returned too.

Here is what I know so far:
1. The ace fluid is just below the max level, engine running or not, and it swirls around as it should.
2. ACE fluid level is not leaking. I've had a consistent level for months. No fluid under the car or visible on ace components.
3. ace block filter was changed about 7 months ago.
4. pressure control valve swapped with a known good one, so not that.
5. ace ECU swapped out with a 2nd hand one, so probably not that either (maybe I got a faulty one, but I don't think so).

So I have ruled out (wisely or not I don't know :confused:) that it's not the ECU, Pressure control valve, earth cable (no error codes if that was it, i am told), not the pump, the filter or low/bad fluid. No leaks anywhere to be seen.

Then my red light and chime came on while I was at low speed, about 5km/h. Shut off the engine. Restarted and I am back to amber where i have been the rest of the journey to work and back (about 1 hour driving).

New DTCs after the red light district was entered include:
DTC 18 Closed looppressure not under control
DTC 21 Pressuresignal stuck at a valve
DTC 45 Same asbefore: The PCV current has been below a threshold for a time, when acurrent has been demanded.



I'm considering a replacement valve block but the readings I am getting along with the DTCs make it look like no current is reaching any component at all. Accelerometers are at max variance G (I am assuming a max variance reading is equal to no reading), pressure valves, battery everything else is at minimum amps (again, I'm assuming no current, not a measured current of 0).

I'll get to the bottom of it even I replace the whole damned system 1 part at a time. Will also report back here for anyone else. In the mean time do any ACE veterans have advice, insults or tips? It's an expensive job in both time and money to replace the valve block.
 
chris- said:
I'd like to resurrect this old thread as it has helped me a lot so far and is near the top of google searches for ACE amber lights problems.

I am having the same problem with the same data read from a hawkeye as greenmonster on page 4.

My amber ACE light came on and I got these error codes:
DTC 22 Pressuresignal out of range.
DTC 23 Invalidpressure signal received.
DTC 42 Thecalculated temperature has exceeded a threshold for a time.
DTC 45 The PCVcurrent has been below a threshold for a time, when a current hasbeen demanded. [Note PCV = Pressure Control Valve]

Reading from the Hawkeye are:
Upperlateral acc -1.43 G
Lowerlateral acc -1.43 G


DirectCtl Valve1 0.01 Amps
DirectCtl Valve2 0.00 Amps


Batteryvoltage 0.03 Amps
PressureCntrl Valve 0.00 Amps
Pressuresensor 0.00 bar
ResidualPressure 20.00 bar
Systempressure 0.00 bar


Ignition switch ON
Pressure switch ip Not reverse
Main relay OFF

I cleared the DTCs and ran the haweye's system test: with these results:
pressure sensor 0.00 bar
Residual pressure @ 5.2 bar. (don't understand how this is now not 20 bar?)


Direction valve 1 1020 ms ON time (should be 15-60ms)
Direction valve 1 20 ms OFF time (should be 15-60ms)
Direction valve1 1020 ms SYSTEM time (should be 100-250ms)


Direction valve2 1020 ms ON (should be 15-60ms)
Direction valve 2 32 ms OFF time (should be 15-60ms)
Direction valve2 1020 ms SYSTEM time (should be 100-250ms)


Pressure valve 1020ms ON time (should be 4-50ms)
Pressure valve 1020ms SYSTEM time (should be 0-90ms)

DTCs that returned after the test were just the DTC 45. After driving the others returned too.

Here is what I know so far:
1. The ace fluid is just below the max level, engine running or not, and it swirls around as it should.
2. ACE fluid level is not leaking. I've had a consistent level for months. No fluid under the car or visible on ace components.
3. ace block filter was changed about 7 months ago.
4. pressure control valve swapped with a known good one, so not that.
5. ace ECU swapped out with a 2nd hand one, so probably not that either (maybe I got a faulty one, but I don't think so).

So I have ruled out (wisely or not I don't know :confused:) that it's not the ECU, Pressure control valve, earth cable (no error codes if that was it, i am told), not the pump, the filter or low/bad fluid. No leaks anywhere to be seen.

Then my red light and chime came on while I was at low speed, about 5km/h. Shut off the engine. Restarted and I am back to amber where i have been the rest of the journey to work and back (about 1 hour driving).

New DTCs after the red light district was entered include:
DTC 18 Closed looppressure not under control
DTC 21 Pressuresignal stuck at a valve
DTC 45 Same asbefore: The PCV current has been below a threshold for a time, when acurrent has been demanded.



I'm considering a replacement valve block but the readings I am getting along with the DTCs make it look like no current is reaching any component at all. Accelerometers are at max variance G (I am assuming a max variance reading is equal to no reading), pressure valves, battery everything else is at minimum amps (again, I'm assuming no current, not a measured current of 0).

I'll get to the bottom of it even I replace the whole damned system 1 part at a time. Will also report back here for anyone else. In the mean time do any ACE veterans have advice, insults or tips? It's an expensive job in both time and money to replace the valve block.
Click to expand...
Its been a while since I've been on here (sold my D2.) I replaced the ACE ECU with another and all the ACE issues were cleared after that. Replacement didnt need any programming. Just make sure that the part number matched.
 
greenmonster said:
Its been a while since I've been on here (sold my D2.) I replaced the ACE ECU with another and all the ACE issues were cleared after that. Replacement didnt need any programming. Just make sure that the part number matched.
Click to expand...

Hi, I tried that too albeit with a newer version of the control unit. The ACE is still a problem on this Disco after 2 years! I just drove around in lock-down mode, and then the gearbox went and then it got an oil leak... I should probably just sell it but I commute by train so it's more of a hobby than it is transport... haha :(

Disco is currently with local LR independent and they can't find out what is going wrong with ACE either.
Bu then they told me that the system isn't getting power. Hopefully an auto-electrician can find the fault. I will report back for others if ever I find out the problem.
 
I never had problems with ACE until I replaced a hose between reservoir and pump. I saw older hose as "not original one" because its position was not good. Newer hose, a genuine one, was exactly the same shape so I intended to route it in another way. After that, every time I turned to the right, yellow ACE light turned on. After Nanocom check I found different fault codes, with no sense, no sense if I didn't suspect trouble was mi work with this hose....
So I re-routed the hose as initially was made and trouble has gone. I think hidraulic fluid was difficulted to flow trough the hose when engine lightly moved to the left.
Electronic assisted things had in my opinion the trouble that people think electronic is the culprit, but real trouble is a phisik trouble. May be this case can be a not good working pump or a knucked hose... couldn't be?

Regards
 
Hi All,
For what its worth I had all these problems, and an awful lot more, with a 59 reg Disco. It was my fifth Discovery, and more trouble than all the rest put together. A lovely thing when it was running right, but overall a real money pit that tested my sanity.
One glorious day I solved all of the problems. I sold the b..... thing, and replaced it with a 2008 Defender Puma. Its now sheer joy to make a journey confident that I will get back without a warning light of one type or another coming on, it shutting down to limp home mode, or the need to call out a recovery unit.
Perhaps I was just unlucky?

.
 
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