[1.2 TDI ANY] hydraulic oil pump constantly running

Germantas · Gestern um 09:18

Sorry that I am writing in English. Like all of you my Audi a2 1.2 tdi have a problem with gears shifting. I spend a lot of time to read all problem related forums but didn’t find solution. My A2 hydraulic pump was running all the time, and I decided to change an accumulator tank. I bought new one Febi (with adaptor) and use one with a pump from my friend (5-6 gear changes before starts pump). Clutch disengaged at 1.84v and engaging 3.85. Did basics adjustments. Problem: pump is running constantly when engine is on. Car starts in S and N but won’t run. When I change to D or R car engine is revving but not drive because clutch is ON. VCDS group 3 showing Clutch position (Actual) 99.6% and Clutch position (specified) just running in a circle from 2% to 75% and back. Some time, when I start a car in N and then to D is disengage clutch and it drives and changes gears, but pump is running constantly. There is no leakage in a system. I on the way to buy a new clutch cylinder, but not sure it will help, and is not so cheap just to buy it and try. Can someone have advice?

There is video from VCDS:

Lupo_3L · Gestern um 09:36

You say pump is running constantly. Question number 1.: Is there enough hydraulic fluid in the system?

The pump should definitely not run constantly. Even with a bad pressure accumulator it would not constantly run.

Germantas · Gestern um 10:10

Hydraulic fluid I changed to new and level is correct. When I open a door ,pump is running for maybe 30 sec, then stops until I start engine. Then will run again 30sec. Will stay until press a brake or trying to change a gear. When test run a car, I hear that pump is run constantly, because clutch is engaging and disengaging and gears is changing. Sounds like accumulator tank is bad, but it is totally new and even tried with use one who works perfectly on another car.

**Eumeltier** · Gestern um 11:11

Your video don't show the value of the clutch cylinder (G162). As the clutch position is shown at ~100%, the voltage value for G162 should be constant near 4V. Is this correct?

But you write:

vor einer Stunde schrieb Germantas:

clutch is engaging and disengaging and gears is changing.

Because if the clutch cylinder would be active engaging and disengaging all the time, the constantly running pump would be understandable. But the 100% value would say that the clutch is and stays open the whole time.

Your video, is it in D or N? Does anything change if the motor is not running?

Germantas · Gestern um 13:04

VCDS show 99.6% and voltage is if i remember correctly 3.85v. I did video when engine is running, and gear shifter is in D. When I am starting a car in S position, then go to N and D, engine just revving buy car not driving (my video did in this stage). But, when starting engine in N and then to D, not always but often, clutch is disengaging, and I can drive. I didn't check how is when engine not runs. Will do it today. What more i can try or read with VCDS to be shure there is a problem?

**Eumeltier** · Gestern um 13:14

I would check following situations:

Motor off, N
Motor off, D

Motor off, D, brake pedal pressed

Motor on, N
Motor on, D

Motor on, D, brake pedal pressed

What happens in each situation with the G162 value and the both clutch position values?

Germantas · Gestern um 15:42

I made a video where i showing what is happening with a gearbox:

**Eumeltier** · Gestern um 16:00

There are some strange readings.

If you are in N, the clutch should be pulled. And regarding to your readings, it is.
But the target value (clutch position specified) is changing. As it should close.
In N it should never close.
So first - why is the control unit wanting to close the clutch? And furthermore, why is the clutch not closed, if the control units wants to? (even if it is not correct to close the clutch in N...)

You have not filmed the instrument cluster the whole time. I remarked when you selected D, there was no gear shown in the display.
What happens if you change the lever to the left - tiptronic? Are the numbers 1 to 5 shown?
If you do this with motor stopped, you should also be able to change the selected gear with + and -

Did you try to do the basic setting?

Germantas · vor 23 Stunden

"So first - why is the control unit wanting to close the clutch?"

Gearbox in D and no brakes. Clutch need to be closed and car need to drive. This is my understanding. Sorry for video,i not made it to show all. But mostly i will show that car engine starts in S or N, but when switching to D or R clutch still open and car can not drive. And pump os constantly running.

**Eumeltier** · vor 23 Stunden

No no,

at 5:06 you are in N and the "Clutch position (specified)" is going down to 0.2%, so the control unit says the clutch should be closed.

In N the clutch should be open. And regarding to G162 and "Clutch position (actual)" it IS open. But the control unit says "close".

So, why does the control unit wants to close the clutch in N? And if the control unit wants this (even if it's wrong), why is the clutch not closed?

There is something total mixed up.

Did you tried the basic setting?
https://wiki.a2-freun.de/wiki/index.php/Getriebegrundeinstellung

Edit: I think this discussion should get it's own thread. Maybe an admin can move it?

Bearbeitet vor 23 Stunden von Eumeltier

Germantas · vor 23 Stunden

You are totally right! Spend lot of time to read English and German forum about gearbox problems and solutions. Wrote to this forum because i'm confused and can't find a answer what is it. For example, yesterday i just started engine and test drive s car without a problem. Just pump was running constantly. Then i decided to drive a car to a garage and got this problem some was from las weekend when i change accumulator tank ang fluid. From my video you see, when car is in D snd brake is released clutch specific values is moving up and down, but actual is always showing 99.6 %, it's mean clutch is open. Why...?

Germantas · vor 22 Stunden

I already contacted Mankmil for new clutch valve,and he wrote that it need to be changed by age and millage. But want to understand if it helps

**Eumeltier** · vor 22 Stunden

At this moment I don't see the evidence that the clutch valve is the problem.

The clutch valve needs the hydraulic pressure to OPEN. But it is open. All the time.

Did you see the clutch closed with VCDS? If you just turn the ignition on with the lever on STOP and no break pedal pressed, is the G162 below 2V?

If the clutch is still open, disconnect the electric plug at the hydraulic block and release the accumulator tank 1/4 turn. Then all hydraulic pressure is gone and the pump won't work anymore. At this moment the clutch must be closed.

If it is still opened without hydraulic pressure, I assume a mechanic defect with the clutch itself. Then the new clutch valvue won't help at all.

So I think at first you have to be sure about the reason for the problems before changing any parts.

Germantas · vor 22 Stunden

Yes,i see clutch is closing some times. But you are right, maybe is some mechanical problem and is stuck and some time just release. Now is dark, will try to do the same test, but will try to move by hand a clutch lever. And, if i have this situation, it's mean clutch leaver need to be pulled ans stuck,but clutch valve cable need to be pulled off?

Bearbeitet vor 22 Stunden von Germantas

**Eumeltier** · vor 22 Stunden

If your clutch won't close and you want to exclude that it is because the hydraulic system gone wild for some reason, you have to release all pressure.

https://wiki.a2-freun.de/wiki/index.php/Getriebegrundeinstellung#System_drucklos_machen

I don't know if you can read any german?

- Loose the coolant tank and put it aside

- Remove the black electric plug at the hydraulic pump. So the pump won't work anymore
- Loose the hydraulic accumulator tank by 1/2 turn. So the pressure is released, all hydraulic oil will go back into the reservoir

After this the clutch has to be closed, because there is no more hydraulic pressure left.

If the clutch is not closed, then you have a mechanical problem.

Don't forget to tighten the accumulator tank before connecting the pump again, otherwise the oil will spill...

Germantas · vor 22 Stunden

I know how to do this. I did it more than 10 times. Will do this tomorrow one more time. Funny, i learned a German in school. But it was 30 year ago. And if you not using it in your life, you forgetting it.

I have 5 pcs. Audi A2. Two is 1.4i,two is BCB( did swap). I decided to buy 1.2tdi and didn't imagine that it will be so complicated:)

Bearbeitet vor 21 Stunden von Germantas

**_Manni_** · vor 21 Stunden

Maybe you start your one thread with information, instead of posting in the KNZ hall sensor repair thread.

Only a hint

Germantas · vor 12 Stunden

8 hours ago, _Manni_ said:

Maybe you start your one thread with information, instead of posting in the KNZ hall sensor repair thread.

Only a hint

I will happy to do this, but i'm not German and don't know how are people reacts when i writing in not forum native language. I can use a google translate, but can't be shure if it translate correctly

**Eumeltier** · vor 11 Stunden

There is the special english sub-forum:

https://a2-freun.de/forum/forums/forum/57-english-language-forum/

**_Manni_** · vor 9 Stunden

vor 1 Stunde schrieb Germantas:

vor 10 Stunden schrieb _Manni_:

I will happy to do this, but i'm not German and don't know how are people reacts when i writing in not forum native language. I can use a google translate, but can't be shure if it translate correctly

You dont need a german passport to start a thread here

And you see... We try to speak english with you without a problem.

DerWeißeA2 · vor 8 Stunden

Moderator:

Thema in passendes Unterforum verschoben.

Lupo_3L · vor 6 Stunden

The fault "clutch pressure system" would lead me to the assumption, that the pressure accumulator is very old. This could lead to this specific fault code.

**Eumeltier** · vor 5 Stunden

Yes, I had this error code with my green 1.2 TDI.

The pump was running after every gear shift. And sometimes the clutch didn't open fast enough when stopping. The problems where solved with a new pressure accumulator.
But I don't think this is the only reason for the problems of Germantas' car.

Lupo_3L · vor 4 Stunden

When this fault is saved, it's very likely the reason.

Bearbeitet vor 4 Stunden von Lupo_3L

Germantas · vor 2 Stunden

Now looked to clutch leaver. Clutch cylinder moving it just les ten 10mm. I tried to puch it with bid metal stick, but it can't move . If it stuck,it stuck in very strange position. Maybe pump is running almost without a stop to trying create a pressure to move a leaver. My question is: how hard is to move clutch leaver to open a clutch? I think,a problem is with mechanical clutch parts and to be shure i need remove gearbox.

Bearbeitet vor 2 Stunden von Germantas

**Eumeltier** · vor 2 Stunden

vor 16 Minuten schrieb Germantas:

Maybe pump is running almost without a stop to trying create a pressure to move a leaver.

I don't think this is logical. According to your VCDS readings the clutch is open and won't close. But the hydraulic pressure is needed to open the clutch. Not to close it.

**Eumeltier** · vor 2 Stunden

vor 2 Stunden schrieb Lupo_3L:

When this fault is saved, it's very likely the reason.

I can not imagine that it would be the only reason for all the strange effects.

But if course it should be checked. But Germantas wrote he already replaced the hydraulic accumulator with a new one.

Also we don't know what he has already tried with the car and if this error is real or because some experiments. So it would be interesting if the error comes back after clearing it.

Germantas · vor 1 Stunde

Little of history: A2 is 2005 with milage 240 000km. I bought it two weeks ago. Previous owner told that car drive good,but when engine is warn,it won't start. This is indication of worn injectors gaskets and i replaced it. Can drives well, gears is changing smoothly. I never had before this car and can't compare with another. It was two problem left. One is turbo vastgate accurator not working and gear box hidtaulic pump starting after first gear change. When i checked hydraulic system, recognize that instead of green oil it was filet with red ATF. Don't know why. There was visibal leakage. I bought new Febi accumulator and adapter for it. Replaced correct oil and installed Febi. Did all adaptations. Car car drive,but pump still working almost constantly. I bought nother pump with confirmed working ( 4 gears change) original accumutor,but results is the same. Now after last test drive i got this situation where i explained early and in video

**Eumeltier** · vor 29 Minuten

roughly 250.000 km is the milage where problems starts with the "Führungshülse" and the G162 value (therefore Mankmil built the hall effect modification for the clutch cylinder to never have this problem again).

Did the previous owner told you anything about repairs at the gearbox, the clutch itself and the "Führungshülse" ?

If the Führungshülse hasn't changed yet it is highly probable defect - regardeless if this has something to do with your actual problem.

[1.2 TDI ANY] hydraulic oil pump constantly running

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