I think you have a good case as you logged the first fault within the warranty period. There is such a difference between dealers and a good one is worth hanging onto. My dealer replaced the Haldex within days of the warranty expiring as at the service they had seen a small oil leak that they could not account for. Such a difference to your experience sadly.

Like you I'm of a certain age and have had dealers with a similar attitude to yours. I really hope you manage to get it sorted without to much hassle but if it comes to it stick to your guns you've got nothing to lose.

Just found and read the article by Voxmagna about the Haldex pump and filter with pictures!!! Brilliant well done.

 

One question what does the filter filter out of the oil?? as you say it is supposed to be a 'for life filter' what time scale is this ?bit of an open ended statement that.

 

Did you see any small paticles or anything that would make you say that this filter does need to be binned and a new one fitted?

 

Last question why does the Haldex oil need to be changed after  3 years or xthousand miles? power steering  oil used to go on for years without being changed just a top up in the tank under the lid if needed. I had an autobox Saab many years ago and that never had the oil changed in the box whilst i had the car for 5 years and i did over 110000 miles.

 

Ita all a bit odd.

The auto manufacturers consistently claim a 10 year design life.

Just found and read the article by Voxmagna about the Haldex pump and filter with pictures!!! Brilliant well done.

 

One question what does the filter filter out of the oil?? as you say it is supposed to be a 'for life filter' what time scale is this ?bit of an open ended statement that.

 

Did you see any small paticles or anything that would make you say that this filter does need to be binned and a new one fitted?

 

Last question why does the Haldex oil need to be changed after  3 years or xthousand miles? power steering  oil used to go on for years without being changed just a top up in the tank under the lid if needed. I had an autobox Saab many years ago and that never had the oil changed in the box whilst i had the car for 5 years and i did over 110000 miles.

 

Ita all a bit odd.

 

 

No, not really. As I understand it, the unit is a 7 plate sintered metal "wet" clutch. So it's not an auto/torque drive sort of thing, nor is it like a hydraulic power steering pump, which merely pushes fluid round in circlesl

 

The plates are spring tensioned/loaded to take up any slack to give immediate response, which gives rise to the ?% drive to the rear wheels in "normal" driving conditions. This means they slip a lot and hence probably wear slightly - so any bits might be clutch plate debris. The Haldex fluid seems to have to work hard, so I guess replacement fluid is probably a wise move.

Don't forget, it's not an on/off situation - the various ecu's  progressively tighten the clutch pressure on demand, although the process might be quiet rapid in a demanding situation. Clever bit of kit, which is probably why Borg Warner bought it and cheapened it Gen V.

 

Just my understanding of Haldex IV data if you read it carefully.

Here is a better priced replacement filter

 

http://www.hstuning.com/product_info.php?products_id=3975

Here is a better priced replacement filter

 

http://www.hstuning.com/product_info.php?products_id=3975

 

Not really. From the US, so postage will be enormous and on top of an inflated price,  

 

Mine cost £33 from my local Volvo dealer last week.

Not really. From the US, so postage will be enormous and on top of an inflated price,  

 

Mine cost £33 from my local Volvo dealer last week.

Have you got a part number for this Volvo filter. I tried buying one at Skoda yesterday but they had no knowledge of any filter within the Haldex, they even showed me their part diagrams which neglect to itemise it.

 

I've been putting up with FWD for some time now (sporadic clutch failure error) and yesterday I figured I'd investigate by dropping the oil and checking the condition of the filter. The fluid that came out of the drain point was very clean. I then removed the Haldex pump and got some fairly grey oil out of here. The pump has a half moon shaped screen filter on the end and on mine it was completely covered in a grey paste which would have been impeding the oil flow. I then pulled the main filter (the one that doesn't exist) and it had the same grey paste the screen filter was covered in.

 

Long story short, I cleaned the filters, refitted them and filled up with fresh oil. Today it has been pouring with rain so I had an excellent opportunity to test it and my 4WD has returned to normal functionality :clap: who knows how long it'll stay this way but for now I'm happy that I don't have the understeering monster   

 

My Haldex fault code is back!

The dealership informed me that the scan was a legal document and that they couldn't let me have a copy!...Despite agreeing that the Haldex error code did exist using their scanning equipment they also informed me that I risked invalidating my warranty by doing a scan of my own using my VAG VCDS cable (Genuine Ross-Tech using 15.7.4 version, not a Chinese knock off)

I haven't scanned it since the dealer reset the codes, but the car goes into the dealership again on Wednesday so I'll see what the outcome is..I can understand that they probably get owners who do performance mods to their cars, but with my 61st birthday coming up this week, I'm hardly some boy racer with brightly coloured brake calipers, vacuum gauges and blow off valves hissing at every gear change..I drive like a saint  

 

The car is just out of warranty by about 6 weeks and goes into the dealership on Tuesday 22/8/2016. I'm hoping I don't have a bun fight with the dealer on getting this rectified out of warranty although when I notified them it was within the warranty period.

I've raised a report with Volkswagen Customer Care to cover my arse so watch this space.

 

 I'm pleased to say that I received a phone call from the dealership and Skoda have agreed to replace the pump..I now have to wait for it to arrive from Germany and they promise that it will be fitted as soon as it arrives along with replacement fluid.

They also gave me a copy of the diagnostic readout confirming what my VCDS had already picked up on. You could say that I feel a little less concerned and I was impressed with 2 people at the dealership who delivered what they promised, namely keeping me in the loop!

Have you got a part number for this Volvo filter. I tried buying one at Skoda yesterday but they had no knowledge of any filter within the Haldex, they even showed me their part diagrams which neglect to itemise it.

 

I've been putting up with FWD for some time now (sporadic clutch failure error) and yesterday I figured I'd investigate by dropping the oil and checking the condition of the filter. The fluid that came out of the drain point was very clean. I then removed the Haldex pump and got some fairly grey oil out of here. The pump has a half moon shaped screen filter on the end and on mine it was completely covered in a grey paste which would have been impeding the oil flow. I then pulled the main filter (the one that doesn't exist) and it had the same grey paste the screen filter was covered in.

 

Long story short, I cleaned the filters, refitted them and filled up with fresh oil. Today it has been pouring with rain so I had an excellent opportunity to test it and my 4WD has returned to normal functionality :clap: who knows how long it'll stay this way but for now I'm happy that I don't have the understeering monster 

 

Part number 31325173 - £33.12 in UK money.

MY12 Yeti  (50k) Gen4 Haldex oil and filter was clean when i looked at it a few months ago. VCDS now flags the open circuit pump motor fault others have reported and reports voltage but no current taken by the motor.

 

I'm hoping there are some 'outside the box' engineer types like me that can post up hard info. on the Gen4 Haldex. Has anybody looked at the wiring, are there connectors which might go bad? Has anybody removed a pump motor and gone inside? I'm curious to know if this is the kind of motor with flimsy brushes that is going to shout 'unreliable' at me or have they been clever and put an over temperature cut out in the armature windings? or are their motor brushes small soft rubbish, or have they got open ventilation which dumps crap on the motor armature, or is the motor electronically commutated.

 

It looks like I'm going to have to get inside and do the autopsy myself when the weather warms up, but any help towards the end goal of explaining the failure and a possible fault cure would be appreciated. Since I do this kind of work myself, I don't keep it secret if it helps others!

 

Along with other VAG parts, the Haldex pumps seem to have high reported failures on discussion forums and it would be nice to find out how they fail and why. If Skoda put in a badly designed or unreliable part, I don't want to replace it with the same

Hasn't there been a thread about water ingress into the external switching unit, and that causing problems?

It's not in this discussion thread which has had a lot of views with vcds results from others the same as mine - pump motor open circuit. Looks like I'll be biting my own bullet and tearing it apart. The Haldex control unit is fed from the same fused power source as the dash panel (which is o.k) and unless the pump drivers in the control unit have failed I'm betting my control unit is o.k because vcds still reports normal valve behaviour. I just need some warm weather to check the motor resistance with an ohm meter first, weather too risky to start anything at the mo. Still, it's a shame Yeti 4WD won't be available for me at the time of year when it could be most needed.

http://briskoda.net/forums/topic/417333-overactive-traction-control/page-3

MY12 Yeti (50k) Gen4 Haldex oil and filter was clean when i looked at it a few months ago. VCDS now flags the open circuit pump motor fault others have reported and reports voltage but no current taken by the motor.

I'm hoping there are some 'outside the box' engineer types like me that can post up hard info. on the Gen4 Haldex. Has anybody looked at the wiring, are there connectors which might go bad? Has anybody removed a pump motor and gone inside? I'm curious to know if this is the kind of motor with flimsy brushes that is going to shout 'unreliable' at me or have they been clever and put an over temperature cut out in the armature windings? or are their motor brushes small soft rubbish, or have they got open ventilation which dumps crap on the motor armature, or is the motor electronically commutated.

It looks like I'm going to have to get inside and do the autopsy myself when the weather warms up, but any help towards the end goal of explaining the failure and a possible fault cure would be appreciated. Since I do this kind of work myself, I don't keep it secret if it helps others!

Along with other VAG parts, the Haldex pumps seem to have high reported failures on discussion forums and it would be nice to find out how they fail and why. If Skoda put in a badly designed or unreliable part, I don't want to replace it with the same

Have you removed the pump itself and had a look at it?

The gauze in the lower region is normally filled with gunge, even if the oil and filter are in good condition.

Low voltage and moisture are obvious enemies for the Haldex.............not like the old days where component wear was all you needed to worry about

Scroll down to the "Generation 4" section here: http://www.haldexrepairs.co.uk/index.html#gen4

Might help ?

O.K Here are all the answers:

 

Haldex Gen4 pump teardown:

 

VCDS scan reports 'motor open circuit'.  First step is to test the motor resistance to confirm it is open circuit.  With the rear of Yeti12 on ramps, locate front large M14 12 point torx and undo it 5 turns to lower the nose of the Haldex coupling and provide additional clearance at the top.  Remove 2 small hex screws holding the Haldex control unit to the frame. Gently twist it around to get the electrical connectors in front of you. The large connector with several wires is the power and control to the vehicle system. The smaller connector with 2 wires is the pump motor. Push in a screwdriver blade through the slot and gently lift up the latch whilst prying up the connectors at the bottom edge to release them. The smaller pump connector is on a very short sheathed wire held by 3 plastic clips, one near the connector, a second half way around at the back and a third close to the pump body. At this stage just test the pump for continuity across the connector terminals. My pump measured 20 ohms. At first I thought this might be o.k. With the ohmeter connected, whack the pump body gently with a wrench and see if the reading changes. Mine went from 20 ohm to open circuit. O.K that confirms my suspicion the motor has a brush fault and you have to dig deeper ( the correct motor resistance should be about 2.5 ohms static).

 

Unclip the motor lead. The middle clip is a pain and requires a dental mirror, light and long blade screwdriver to lift the tongue of the clip. Push the motor cable around until it is free and hanging. Remove the Haldex oil check screw (hex) at the top. Place a catch can under the unit and remove the oil drain screw at the bottom (hex). Remove the 2 hex screws retaining the motor body in the housing. The motor/pump housing is a tight fit in the clutch body being held by two O rings. Using a blunt chisel and small hammer, gently tap the pump body to move the pump assembly out of the body until it is free. Note: to re-assemble, grease the O rings with red rubber grease and use a G clamp to press it back in.

 

With the motor pump assembly removed you will probably see some black/grey crud around the nylon filter gauze at the end.  With the assembly on a clean workbench you can remove 2 screws retaining the filter and clean it in white spirit or kerosene. Note: The pump body cover is under spring pressure and will lift up if the third screw is slackened! Remove 2 small torx screws holding on the cylindrical cover with internal permanent magnet and gently slide it off to reveal the motor armature and brush assembly as shown in my photos.

Check the brush length. I didn't have a new motor to compare but my brush length was 9mm which I thought should be o.k. Using a cotton bud and meths or alcohol, clean the commutator. Check the commutator slip ring is fairly clean without deep gouges - fine scratches are o.k. Using a sharp point or dental pic, gently lift the brushes against their springs in each brush holder. Now spray some switch cleaner lubricant into the brush holders and repeat. Measure the motor resistance which should now be about 2.5 ohms if cleaning has worked. Whilst measuring the resistance, rotate the armature and check resistance fluctuates but still stays around 2.5 ohms. Replace the cover with magnet and 2 fixing screws. Connect the motor to a 12 volt d.c supply (there are no protection diodes so polarity is unimportant). The motor should run smoothly with no fluid load at around 1 amp. You now have a good motor!

Reverse the teardown procedure but don't forget to tighten the front mount support! Filling the Haldex unit through the top fill hole can be a pain. I use a large hyperdermic syring with a silicone tube on the end. Final fill to level (oil coming from the fill hole) should be done with the car off ramps and on level ground. Clear the motor fault with VCDS.

Why does this pump motor fail to open circuit fault? These are my theories: The free running pump current draw is only 1 amp which is pretty small. It can never exceed 5 amp because that is the fuse fitted and shared with the instrument display. The armature appears well made and the commutator is small diameter, which should give low brush wear and long life. However, low voltage low current intermittent operation d.c brush motors can be problematic because there is insufficient arcing to self clean the commutator and any small resistance due to poor brush to armature contact pressure will not start and run the motor. The small brushes and brush boxes can lead to brushes sticking once material becomes trapped inside the brush boxes.
 

I deduced that the Haldex pump motor does not run when Yeti is stationary at idle and VCDS says 'NO' zero current.  I'm guessing NO means no operation and the zero result is therefore correct. However the fly in the ointment is the ignition on self check done by the Haldex controller. It will momentarily pulse the motor to measure the peak current. Normally a motor with a dirty commutator would arc when d.c is first applied, run and self clean. It is my suspicion that once the start up current check is done and fails, the controller locks out the pump until the fault is cleared.  I haven't tried this but I suspect if you removed the motor connection, applied 12 volts and ran the motor a few seconds, you might get a temporary fix - but teardown and thorough cleaning is the best way.

 

MY12 Yeti is ready and waiting for snow, no faults after a test drive and the cost was my time to teardown test and clean. I haven't said what you do if the motor resistance checks out o.k? In this case the fault is most likely the motor drive semiconductor switches in the Haldex control unit. I haven't been inside mine to look, but usually they use a 10 cent smd mos device which can be traced back from the motor connector pins.

 

I can't understand why there is no transmission error warning light for this fault. You can be driving in 2 wheel mode all the time and not AWD and there are probably loads of 4WD Yetis on the road like this. In fact, if you were fed up with these pump motor faults or impending doom from the Haldex unit, I can't see why you shouldn't consider tying the Haldex pump motor to the off road switch. That way you would be in 2 wheel mode most of the time (but with the rear transmission coupled) and only use the AWD mode off road or when you need it. There would be less wear on the Haldex unit and longer life.

 

Nice work :)

How much crud was there on the gauze filter, did it look enough to impede oil flow ?

Hardly any, but more than I found on the main filter at the top, which suggests if you are going to check and clean the filter(s) you should remove the pump motor and clean both.

I noticed something when looking at photos for a replacement pump (which I didn't need). My OE pump has a very shallow strainer fitted on the far end as per photo. But I noticed the same pump with a much larger nylon filter. It's too late now to check the housing depth behind the pump and see if a longer filter would fit in the space.

Question, if I may: where does the crud come from?  I understood the Haldex to be basically a sealed system.  Is there a route whereby dirt can get in somewhere, or is it all just coming from internal wear?

I haven't been inside the mechanics. But from what I could see and feel it is the kind of soft grey sludge you can get from decomposing epdm rubber brake lines seen in a brake master cylinder or from wear on seals with rotating shafts. I couldn't find many metal particles.  It didn't look like extenal road dirt contamination either. I haven't seen this in gearboxes or diffs so I suspect it comes from components used inside the Haldex clutch. MY12 Yeti had done about 50k miles.

 

The motor filter wasn't completely blocked with sludge and I don't believe the sludge that was present contributed to bad brush contact. The pump is a gear pump and as long as there is some oil to wet internal parts, the pump and motor should be o.k to run off load or with a blocked inlet.  However, it looks as though the main filter doesn't trap it completely and the fine stuff in the oil falls to the lowest point which is the pump. If the sludge is from internal epdm parts, they might be wearing or decomposing in the the oil?

 

I have unanswered questions in my head: 1. How does anybody know if their Yeti AWD is inoperative? 2. Is there a simple test or check when used mainly on road? 3. What is the normal duty cycle for the pump motor - is it infrequent or runs a lot? 4. What is the maximum motor current when delivering pressure? I understand the pump can deliver 4 Bar which is pretty high and expect the 1 amp off load current I measured to be much higher in service. VCDS does have a pump motor current measuring block. I will hook up diagnostics, take it for a drive and see what happens under acceleration. I think I know how to fool the diagnostics motor current check at start up to give the motor a chance to start without locking out and it is possible to add a d.c Hall effect current sensor to the pump wire to run a led in the cockpit. Other than that I am out of ideas.

Thanks for that further information.

 

1. How does anybody know if their Yeti AWD is inoperative? 2. Is there a simple test or check when used mainly on road?

 

The only way I know of is to check for fault codes via the ODB port - not exactly user-friendly for the average punter.  It appears that a fault light might be a useful thing to have: I my view anything that is supposed to "just work" should really have a means to alert you if it can't.

 

3. What is the normal duty cycle for the pump motor - is it infrequent or runs a lot? 

 

 

My understanding is that the generation 4 Haldex in the Yeti relies on there always being pressure in the system to operate the clutch; this being how it manages to react quicker to wheel slippage than the previous versions.  What this might mean in terms of the duty cycle of the pump - if anything - I have no idea.

Edited 19 January, 20179 yr by ejstubbs

Simple AWD test? and the one used on the Volvo XC90 forums (the XC90 uses an almost identical setup) is to plonk the front wheels on a wet grassy slope with the rears still on the tarmac/road etc, and floor the throttle, if the front wheels just spin, then you only have 2WD operational. However if the car then tries to push/pull you up the slope also using the rear wheels then the Haldex unit is operational.

 

Hope that helps.

Brilliant work by voxmagna.  Surely this thread deserves to be moved to the Technical Guides now.  Mods?