Hilfe AUDI A2 1.2 TDi springt nicht an

[Arturasz]

Hallo, heute AUDI A2 1.2TDI springt ein nicht ;[ Gestern fuhr nach Hause, aber heute springt Nicht an. Erste, was mir aufgefallen ist, dass wenn ich Fahrertür öffnen Hydraulikpumpe nicht brummt. Wenn ich Zündung an - hydraulischen Pumpe wird auch nicht ;[ Und als Sie ahnen kann ich nicht starten meinem Auto...

 

VAG-COM zeigt keine Fehler im Motor-oder Automatik transmision.

 

Dinge, die ich getan:

 

• Geladenen Akku (es ist fast neu);
  
• Wenn ich Licht und offenen Fahrertür drehen, I Warnton über Leuchten, so ist wahrscheinlich nicht Mikroschalter in den Türen;
  
• Clutch Sender zeigt 1,98 V;
  
• Wetter Temperatur -5 ° C;
  
• Getriebe dargestellt gut (SRNE und 1 in triptronic), aber wenn ich ihnen wechseln kann ich nicht hören Änderungen;
  
• Bremslichter arbeiten.
  

 

Können Sie mir empfehlen, was jetzt zu tun? Sollte ich Grundeinstellung? Aber ich weiß nicht, ist es keine gute Idee, dies zu tun, wenn die Pumpe nicht funktioniert? Ich werde verlieren vorhandene Einstellung.

 

Bearbeitet 16. Dezember 2012 von Arturasz

[Phoenix A2]

Können Sie mir empfehlen, was jetzt zu tun? Sollte ich Grundeinstellung? Aber ich weiß nicht, ist es keine gute Idee, dies zu tun, wenn die Pumpe nicht funktioniert? Ich werde verlieren vorhandene Einstellung.

 

First off its important to determine why the hydraulic pump does not work.

 

Just a few days ago someone had a similar problem. In that case it was a malfunctioning relay + regarding fuse that provides the hydraulic pump with power (under the floor in front of the driver seat where the ECU is placed, too).

The relay sits on slot no.4 and has the label "373" (right beside the blue 60A fuse). Old part number is "8D0 951 253 A" (new part number to ask for at the dealer would be "4H0 951 253 A"). See also within the attached photo.

If you have soldering equipment maybe the relay can be repaired by resoldering the inner contact terminals (cold soldering joints).

Take also a look to the fuse of the hydraulic pump. It's a red 20A fuse and placed at the other side of the same relay tray.

 

Summary:

 

• Check relay that switches power for hydraulic pump
  
• Check 20A fuse for hydraulic pump
  

 

There is a good chance that there is no need for a basic setting when you fixed the hydraulic pump.

 

Good luck on finding the issue:).

Bearbeitet 16. Dezember 2012 von Phoenix A2

[Arturasz]

Checked 20A fuse - it is ok.

Also tried to switch over those two 373 relays. Pump is still not audible ;[

 

Whats next?

[Phoenix A2]

Next:

 

• Check error memory of all controllers especially the one for automatic transmission
  
• Check value of pressure sensor of hydraulic system (transmission controller -> measurement block 20 value 4)
  Anything higher than approx. 2,7V would cause the hydraulic pump to not work as the controller thinks there is enough pressure to start. Then maybe the pressure sensor is faulty.
  

[Arturasz]

Just returned from car:

 

1. Errors are these:

 

VAG-COM Version: Release 311.2-N

 

 

Chassis Type: 8Z - Audi A2

Scan: 01,02,03,08,15,16,17,37,45,46,56,57,75,76,77

 

Address 01 -------------------------------------------------------

Controller: 045 906 019 D

Component: 1,2l R3 EDC 0001DS 1290

Coding: 00005

Shop #: WSC 02138

WAUZZZ8ZZ1N053334 AUZ7Z0A1838307

No fault code found.

 

Address 02 -------------------------------------------------------

Controller: 6N0 927 735 D

Component: DS085 Getriebe 3081

Coding: 00000

Shop #: WSC 00000

No fault code found.

 

Address 03 -------------------------------------------------------

Controller: 8Z0 907 379 B

Component: ESP 20 CAN V015

Coding: 10772

Shop #: WSC 00000

1 Fault Found:

01542 - Yaw Rate Sensor (G202)

57-10 - Electric Circuit Failure - Intermittent

 

Address 08 -------------------------------------------------------

Controller: 8Z0 820 043

Component: A2-KLIMA

Note: Excessive Comm Errors

 

Address 15 -------------------------------------------------------

Controller: 8Z0 959 655 E

Component: Airbag Front+Seite 5005

Coding: 00102

Shop #: WSC 02152

No fault code found.

 

Address 17 -------------------------------------------------------

Controller: 8Z0 920 930 Q

Component: KOMBI+WEGFAHRS. VDO D05

Coding: 00035

Shop #: WSC 01632

WAUZZZ8ZZ1N053334 AUZ7Z0A1838307

No fault code found.

 

Address 46 -------------------------------------------------------

Controller:

Note: Excessive Comm Errors

 

End -------------------------------------------------------

 

 

 

2. Voltage is 2.91V, sometime it drops to 2.89V. Is this can be a real reason? Or it is within small deviation limits?

 

[Phoenix A2]

1. Errors are these:

 

No additional hints here: The one fault within ESP should not be related to the transmission problem.

 

2. Voltage is 2.91V, sometime it drops to 2.89V. Is this can be a real reason? Or it is within small deviation limits?

 

That's interesting. It seems that the pressure sensor detects a pressure although the hydraulic pump is not working. When this value is more than 2,7V the hydraulic pump will not get activated by the controller as it thinks there is enough pressure.

You can double check this if you release the "pressure bomb" half a round to ensure that there is really no pressure inside the hydraulic system (before: look at the level of hydraulic fluid inside the storage tank, when the level is within the rectanglur indicator the pressure should be almost gone). When the value of the pressure sensor remains the same, then the pressure sensor is most likely faulty.

Just in case:

 

6N0 907 597 - Pressure sensor - 99,96€

6N0 142 425 - Seal Ring - 1,84€

 

The pressure sensor is located within the "package" consisting of hydraulic pump, fluid storage tank and pressure bomb.

Bearbeitet 17. Dezember 2012 von Phoenix A2

[Phoenix A2]

Added some photos that should help locating the pressure sensor.

 

Big red circle: Hydraulic pressure sensor (G270)

Small red circle: Bolt that holds the sensor in place

[Arturasz]

Phoenix A2,

 

I unscrewed the "pressurebomb", and voltage went from 2,89V to somewhere 2,4V. So pressure sensor is working ok. Then I heard silent hum of hydraulic pump, then tighten pressure bomb, and checked the value in 20 MVB 4 field - it showed only 3,13V of instead 4V. As I understand pump doesn't generate enough pressure to change gear to neutral. Pump during action is working not as loud as usually. So pump is faulty? BTW, weather is quite cold right now about -10°C. ˆ

[RAB3L]

Phoenix A2,

 

I unscrewed the "pressurebomb", and voltage went from 2,89V to somewhere 2,4V. So pressure sensor is working ok. Then I heard silent hum of hydraulic pump, then tighten pressure bomb, and checked the value in 20 MVB 4 field - it showed only 3,13V of instead 4V. As I understand pump doesn't generate enough pressure to change gear to neutral. Pump during action is working not as loud as usually. So pump is faulty? BTW, weather is quite cold right now about -10°C. ˆ

 

You might need to change the accumulator (or pressurebomb). VCDS cannot diagnose a failing or even failed accumulator.

 

RAB3L

[Phoenix A2]

I unscrewed the "pressurebomb", and voltage went from 2,89V to somewhere 2,4V. So pressure sensor is working ok. Then I heard silent hum of hydraulic pump, then tighten pressure bomb, and checked the value in 20 MVB 4 field - it showed only 3,13V of instead 4V. As I understand pump doesn't generate enough pressure to change gear to neutral. Pump during action is working not as loud as usually. So pump is faulty? BTW, weather is quite cold right now about -10°C. ˆ

 

The 4V is only reached when the engine is running. Without running engine the target value is around 3,2V (pump stops after reaching that value). So that's OK.

 

You might need to change the accumulator (or pressurebomb). VCDS cannot diagnose a failing or even failed accumulator.

 

Yes that's possible (thanks for the more suitable word "accumulator";)).

 

Another test might be useful: What happens to value of pressure sensor (20 MVB 4) and value of clutch slave cylinder (2 MVB 2) when you step on the brake pedal.

My guess: even with faulty accumulator there should be at least minimal movement of the clutch slave cylinder.

Bearbeitet 18. Dezember 2012 von Phoenix A2

[Arturasz]

RAB3L, thanks for your reply. But as i read this forum via google translator, that if accumulator is bad hydraulic pump is pumping very frequently but this wasn't in my case. Before failure, I could change 3 gears within activating hydraulic pump, which is nor good/nor bad ...

We need to investigate, why pump now is working very silent and very lazy ...

 

You might need to change the accumulator (or pressurebomb). VCDS cannot diagnose a failing or even failed accumulator.

 

RAB3L

[DerWeißeA2]

Did you check the hydraulic oil? Not the level, but if there is an emulsion of oil and water. This could be critical at those low temperature! Maybe you have a "Frozen Ingolstadt".

[Arturasz]

Yes saw that oil is in liquid form. But noticed that near the cap there is some formation of ice crystals, but it can be water gas condensation-> and product of freezing

[Phoenix A2]

Another test might be useful: What happens to value of pressure sensor (20 MVB 4) and value of clutch slave cylinder (2 MVB 2) when you step on the brake pedal.

 

At the moment i am a little bit confused about

 

a)a hydraulic pump that is working "lazy" and silent

b)a pressure sensor that detects a pressure within valid range

c)actuators (clutch, gear changer) that are not working?

 

I will wait for the result of the short test above. If possible maybe a second person can watch the clutch slave cylinder directly during test?

 

Did you check the hydraulic oil? Not the level, but if there is an emulsion of oil and water. This could be critical at those low temperature!

That's something that could be checked by moving the car to a warmer place (garage?) if possible. I know easier said than done.

 

Edit: Another idea just before going to bed - Try to take off the cap from the hydraulic oil storage tank, in case the bleeding hole within the cap is blocked this prevents a vacuum.

 

PS: Any further ideas from the community are appreciated, too;).

Bearbeitet 18. Dezember 2012 von Phoenix A2

[Arturasz]

Tried this, both values remained the same, while I was holding brake ...

 

Another test might be useful: What happens to value of pressure sensor (20 MVB 4) and value of clutch slave cylinder (2 MVB 2) when you step on the brake pedal.

My guess: even with faulty accumulator there should be at least minimal movement of the clutch slave cylinder.

[Phoenix A2]

Tried this, both values remained the same, while I was holding brake ...

 

So i assume no movement at all of the clutch slave cylinder.?

 

 

As far as i can consider with the information you gave us here, one of the following is maybe the case:

 

a)Pressure sensor (maybe hydraulic pump, too)

The pressure sensor is faulty and gives wrong values to the transmission controller. That may causes the controller to stop the hydraulic pump even when the pressure is not sufficient. A hint would be the hydraulic oil level-difference between "no pressure" and target pressure. At target pressure the level of hydraulic oil should be lower than around 50% of storage tank.

b)Frozen water inside hydraulic oil

When there is a reasonable amount of water beside the hydraulic oil (emulsion) it can freeze inside the pipes and prevent actuactors from working. Therefore if possible move the car to a warmer place.

c)Hydraulic pipe

It's unlikely but not impossible that the hydraulic pipes have moved a bit out of their jacket (see photo #1). Each jacket has a back-pressure valve that prevents draining of hydraulic oil when the pipes are unplugged. There should be only a small gap between the bracket (holding the pipes) and the base with the jackets(see photo #2). When the pipes are not plugged correctly it's possible that the hydraulic pressure does not get to the actuactors.

 

d)Valve of clutch slave cylinder

The clutch slave cylinder is controlled with a valve that lets hydraulic oil with pressure frequently into the cylinder to maintain the target position of it when disengaging the clutch (e.g. after pressing brake pedal). That's not most likely as i think such a failure should be recognized by the controller and noted inside its error memory.

 

Possible next step if b) is not possible or there is no improvement in a warmer environment:

My advise is to get the cheap used replacement unit (hydraulic pump+accumulator+pressure sensor) you told me via PM that you can buy at a local store.

Some tips for exchanging the unit as dismantling is a bit tricky because of few space to handle with your hands:

First of all unscrew the internal hexagon (photo #3) that secures the bracket with the hydraulic pipes. You may need some extensions to reach it with the screwdriver.

After that take out the bracket carefully with one hand (really: there is no more space;)).

Then there are only 2 more screws (photo #4) that hold the metal plate where the whole unit is mounted. Not forgetting the socket for the electric wires.

 

During re-mounting its important to NOT pull the bracket with the hydraulic pipes with the help of the inner hexagon, but to push the bracket by hand while fasten the inner hexagon.

Bearbeitet 19. Dezember 2012 von Phoenix A2

[Phoenix A2]

d)Valve of clutch slave cylinder

Here i meant a fault of the valve that controls the clutch slave cylinder. You can see that part attached to the hydraulic-unit in post #7 photo #2. It is located right under the pressure sensor. Unfortunately this valve is not available as single replacement part.

A hint can give the MVB 13 inside transmission controller when you step on brake pedal. A screenshot of the values from MVB 13 and 4 during "brake-pedal-test" would be helpful.

 

Summary

With a replacement hydraulic unit (pump+accumulator+pressure+valve for slave cylinder) you could cover a),c),d).

 

Keep us informed about the progress and do not hesitate to ask further questions:).

[Taucher]

@Phoenix A2: Ich find es toll, dass Du einem Neuen wie Arturasz immer gleich hilfst.

Ich habe ja auch schon Deine Hilfe in Anspruch genommen.

[Arturasz]

Seems solved or i think found problem. It was/will be variant b). Pump was producing hissing sound, so decided to replace pressure accumulator, with another one. I unscrewed that one which was on car and saw ice crystal, and very thick mass almost like ice.

 

Also tried to connect another pump with warm hydraulic oil on my cars connector - it works quite happily, which can't be said about mine old pump. So my presumption, that liquid froze in some thin pipes. Also color of hyraulic liquid is like "beige" light brown...

Now I have to wait for + temperatures, or somehow engage Neutral gear and tow it to garage.

[Arturasz]

Also have questions, those two pressure accumulators seems bit different, is it matters?

[Phoenix A2]

Good to see that you have (most likely) found the issue:).

 

Also tried to connect another pump with warm hydraulic oil on my cars connector - it works quite happily, which can't be said about mine old pump. So my presumption, that liquid froze in some thin pipes. Also color of hyraulic liquid is like "beige" light brown...

Now I have to wait for + temperatures, or somehow engage Neutral gear and tow it to garage.

 

Brown color of oil is a certain evidence of emulsion with water. The hydraulic oil e.g. in my 1.2 has green color.

I am thinking if a hot air gun can be of any help here? Otherwise you have to somehow lift the car to reach gear changer and switch to neutral gear by hand.

 

Also have questions, those two pressure accumulators seems bit different, is it matters?

 

Can you find any part number on both accumulators?

I don't know of any changes to the accumulator. I would compare the related jacket of both pumps. If there is no difference visible, they should be interchangable/compatible.

I will look into the parts database to see if there are variations of the accumulator noted, that we have to be aware of.

 

PS@DerWeißeA2: Thanks for the golden tip-ORDEN-.

Bearbeitet 20. Dezember 2012 von Phoenix A2

[Arturasz]

Don't have them on hand right now. One "bomb" has two codes, new one three. Which starts 6N0 like on that picture from ebay

 

 

I see that next week will be warmer: GISMETEO.LT: Orai Vilniuje. Or

So maybe i will wait for it. But what next, remove oil? How to flush whole system? how much liters it is? ANother question, that water got from condensation and slight leaks?

Bearbeitet 20. Dezember 2012 von Arturasz

[Phoenix A2]

But what next, remove oil? How to flush whole system? how much liters it is?

 

In total the system contains less than 1 litre of oil. Unfortunately there is no way to change the oil as easy as e.g. brake fluid. There will always remain some old oil within the system. Especially within clutch slave cylinder as it does not have a designate pipe for reverse oil flow.

 

A practicable way is in my opinion:

 

1.Suck as much oil from storage tank as you can or alternatively dismount it and dump the oil by "180-degree-turn".

2.Refill storage tank with new oil.

3.Do multiple gear changes and clutch cycles to support circulation of oil within the system.

4.Repeat step 1,2,(3) for at least one more time.

[Arturasz]

If there is 1 liter, I think canister contains aprox 0,5 liter. I think I will try suction method, because i think removal is not so easy ;]

[DerWeißeA2]

Say hello to RITA. She'll help you!