Im about to loose it. Bought a 2010 Skoda Yeti with Haldex gen4. 

 

The problem:

4wd works 100% fine when starting the car, driving for 1-5min it stops working. I have snow and ice here at the moment so I'm 100% sure. Restarting the car makes the 4wd kick in again, for a minute or so. This repeats every time. Restating the car makes it work again.

 

Fault codes:

02248 - Intermittent, and sometimes static. Haldex Clutch Control Valve N373

 

Testing equipment:

OBD11 - Pro - Vag

 

What I have done to solve the problem:

 

1. Haldex fluid and filter changed. Cleaned the n373 valve. Still same problem

2. Changed the Haldex pump for a new "original" brand. Still same problem

3. Sent the Haldex ECU to a local Swedish well known company that repairs haldex ECU. Cleaned PCB, extended test on the bench together with N373 valve. It works according to them. Still same problem when remounted. 

4. Changed the N373 valve for another used one.

5. Checked the wiring and connectors and everything seems to be fine, cleaned them anyway. 

6. Changed fuses, haldex one + some others for ABS etc.. 

 

I have tried to run all the output test with OBD11, the pump spins and sounds good. By the sound of it no air in the system. The clutch seems to work. But the whole output test with OBD11 fails. "Marginal conditions not met". I have tried this with the temp >20 degrees celcius. Several times. 

 

I have tried live recording of voltage, amps etc.. but OBD11 seems very unstable and just disconnects or perhaps the ECU stops responding. The current of the pumps seems to run in the 2-3A area 

I have probably read every thread in every forum on the internet about 02248 and N373 related problems

As i understand it the Gen4 Haldex has no pressure sensor and according to haldexrepairs doesn't need a "relearn" process as the other gens. 

What should I do? Since it work just fine for a while I don't think it has anything to do with mechanical failure of the clutch, dif etc.. and I get the fault code everytime it stops working... 

 
 

Hi Johann

 

You seem to have tested most things. I recommend that you double check that the Haldex unit is getting full battery volts, as it would only take about one ohm of excess resistance somehere in the feed or ground cables/connections to cause significant voltage drop and then operation problems. Even fuseholders can develop tarnish, try pulling the fuse out and putting it back a few times to clean this.  I suggest you wire up an independent voltmeter inside the vehicle (with extension wires/probes) connected to the 12 volt feed and ground return at or near the connector to the Haldex.  Maybe when the control valve solenoid warms up its electrical resistance increases just enough to stop it working ? Copper resistance increases roughly 10% for a 30 degree C rise.

 

This website has some useful information:  https://www.haldexrepairs.co.uk/guide-generation-4-haldex-trouble-shooting/

Thanks for the reply Austin 7. 
 

Im also prone to think it might be the wiring or ground. I’ve looked for a wiring diagram but if anyone has instructions of where the cable connects to the main ECU I would be thankful. 
 

Im also trying to get hold of another Haldex ECU just to exclude it as a problem.
 

Since my unit doesn’t use a separate ground wire I’ll also try to run a new separate wire from the ECU to the ground. Would it be enough to run it from one of the screws?

Hi

 

I attach the self study program SSP070 for Skoda.

 

Also, you can find some Haldex schematics here: https://www.vdveer-engineering.nl/en/information/haldex-4motion/haldex-schematics

 

I attach a PDF of the one for the Golf 7, it's in German.  Note that TSAA is the connector for the 4WD unit, and 197 is the Ground Connection in the Rear Wiring Harness.  So the unit should be grounded via this wire (br = Brown, 0.75 square mm cross-section).  It should not be necessary to add any extra ground wires. Another thicker brown wire goes from here to Point 6, the Ground point on the rear left frame.  I suggest you check out both these wires carefully for corrosion etc.

 

Power comes from one Fuse via a Red and White wire of 0.75 square mm, Fuse number depends on the year for this example.

 

There are three thinner control/data wires which go the unit marked J533, the diagnostic interface to the data bus.

 

Your vehicle may differ in detail, but I would be suprised if it is very much different.

SSP 070 All-wheel drive with Haldex coupling Generation IV.pdf

Edited 20 January, 20242 yr by Austin 7

Thanks!

 

I’ve now measured the wire loom under the rear left back seat. 
 

Perfect ground and same voltage as the battery (car side). No resistance in the wires to the Haldex unit. All measured separately with about 0.1- 0.2 Ohm. No visible wear or corrosion. No corrosion on the front left ground point. 
 

Seems like my Haldex only runs two control/data wires. At least the wire loom from the car side only has two orange data wires and 12v + ground. 
 

So now I’m in the blind again. Perhaps I’ll try a new battery before ordering a new or used Haldex controller. 
 

Just strange that the controller tests 100% healthy on the bench at the repair shop. But then again, it’s not in the car.. and 4wd also works 100% for a short period when test driven. 

With VCDS you can see the percentage of engagement of the Haldex while you are driving (in a safe place) or by graphing using live data but I could never work out how to do the latter.

 

It is very revealing to see when and under what circumstances it kicks in and even when engaged it momentarily disengages periodically to prevent any transmission wind up.

 

If you can do that in OBD11 then I would look and see if it is being commanded at the times you percieve it not to be working when it should, if it is then it will be a mechanical or electro-mechanical problem, if it isn't then you start looking at other sensor inputs that would inhibit it, I cant think of any other than the obvious wheel speed sensors but it would be a case of the software being written so that the Haldex cannot be commanded when the handbrake is engaged for example, and by chance that is a good example because it is a real one!

J.R. Tried live data recording with obd11 as it has this feature (at least on android). But either my obd11 (original) is loosing connection as all values turns to 0 repeatedly or my Haldex controller has issues. The connection for live data recording is to flimsy either way. 
 

Why I’m thinking it’s not mechanically or electro-mechanically related is because it immediately works once the car is restarted. It always stores the 02248 fault code. It’s almost like when the controller gets that code it shuts of completely until the next drive cycle. 4wd works after restart regardless if I clear the fault code or not. Probably does this to reduce the risk of further damage to for example the pump or n373 valve. But in my case everything works once restarted.
 

I’ve tried to get hold of a VCDS but failed. I think I will try again. 

 

Also my obd11 doesn’t work to reach basic settings. I just get “channel” when entering it and no matter what channel I choose it just says “function not available” I think. 

Double posted. Sorry. 

Edited 20 January, 20242 yr by johanfalkman
Double posted.

And also JR, if another sensor like the break or ABS would send a signal to stop the Haldex. It would not be stored as a fault code to my understanding. In my case it’s always the 002248 present when the 4wd stops working. 

Have you watched the voltage (best with a tester in the 12v socket between seats) to see if anything happens when it loses the rear drive?

Urrell, good idea. I’ll try that and get back!

I havn’t hooked up a separate tester. But obd11 reports good voltage at terminal when the 4wd looses it’s function. 
 

I managed to get this reading from obd11 when it has happened. So it is clear to me that the Haldex controller stores a fault code for the clutch (n373), opens up the n373 valve and keeps it like this until the next drive cycle. 

 

I also tried with another good battery in the car, same problem. 
 

I’m still guessing the controller is still bad and was not really repaired. Waiting for the repair shop reply to if they have another controller. 

Edited 21 January, 20242 yr by johanfalkman
Added picture

Update: Managed to get hold of a 0BS907554B controller. I originally have a 0BR907554B controller. 
 

I guess the difference is that the OBS is for automatic transmission cars, mine is a manual. 
 

And the 4WD now WORKS!

 

I got rid of the N373 error but now have a 01315 (Transmission Control Module - no signal) which I guess is because my car doesn’t have a TCM module. 
 

So should I just keep on driving and be happy? Could this new module have adaptation values that will destroy my Haldex clutch or something else?

 

my conclusion is that the “repaired” original controller is still bad. 

Hi, how did you locate the inside/cabin connectors for the controller? I was told they should go through the floor under the seats, which would also make sense visually, but have trouble removing the carpet attached to the frame. My workshop manual is either incomplete or just avoids describing this and I've already damaged one of the rear clips. Would appreciate it a lot, was unable to find this in the other threads and want to connect a haldex controller without damaging the interior trim! Thanks

If i remember correctly, it was just there under the seat. Yellow thing in my pictures above. 

Thanks, that's what I was as well (and the frame picure with two big holes would agree). But there's a very uncooperative carpet under them,  and it looks the rails securing the seats would need to go as well. The yellow thing should be filling up the hole and holding the cables from the pump and the controller unit.

On 25/01/2024 at 17:30, johanfalkman said:

Update: Managed to get hold of a 0BS907554B controller. I originally have a 0BR907554B controller. 
 

I guess the difference is that the OBS is for automatic transmission cars, mine is a manual. 
 

And the 4WD now WORKS!

 

I got rid of the N373 error but now have a 01315 (Transmission Control Module - no signal) which I guess is because my car doesn’t have a TCM module. 
 

So should I just keep on driving and be happy? Could this new module have adaptation values that will destroy my Haldex clutch or something else?

 

my conclusion is that the “repaired” original controller is still bad. 

Hey Johan,

What did you end up doing I the end, did you keep the automatic one?

Also, where did you get a hold of an N373 valve in Sweden?