4Motion Not Working: Troubleshooting Guide (Solution)

Hello everyone.

Last week, while driving in the snow, I noticed that my 2006 Passat 3C BMP...
has transformed from a 4Motion vehicle into a front-wheel drive vehicle...
The reading from the Haldex control unit showed the following:
Error code 01073: Printing system - clutch, lower limit exceeded.
Es war da am Anfang, beim ersten Auslesen auch noch eine 2. Notification.
Something like a sporadic mechanical malfunction.

The error (related to the clutch pressure system) cannot be cleared while the engine is running and the vehicle is stationary.

Has anyone else experienced something like this before, and do you know of any solutions?

Best regards, Jan.

Hello...

Without really knowing much about it:

Hydraulic unit failure.
Oil level too low.
Oil is very old.
Oil/oil filter is dirty, causing a valve to "stick".
ECU failure.

SG
Alevuz.

Thank you for your reply!

Okay, so the oil and filter are only about 5,000 km old, and that's enough.
Oil is also included in it.

I performed the actuator diagnosis and found the following:

At the "Pre-charge pump" setting, the first power indicator illuminates.
set a value of 2.58 amperes, but the pump is not making any noise.
and the pressure display remains at 0.0 bar.

Should the pump be making a noise?

Regarding the all-wheel drive system, you can hear the valve switching.
And also, the valve retracts as it exits this [area/position].
"Testpoint is now speaking."

I will measure the voltage directly at the pump as soon as possible.
try.

Best,
Jan

Okay, who changed the filter and oil? Tell people here about the history of that part; maybe someone will know more.

I replaced the filter and oil myself, and I was extremely careful to do it correctly.
that there is enough oil.
I checked the oil level again two days ago -> it was fine.

The vehicle has 130,000 kilometers (approximately 80,000 miles) on the odometer, and according to the previous owner, it has...
"It never caused any problems. I've driven it for the last 20,000 kilometers."
and it only caused problems...
I don't know how reliable the statements of the previous owner are.
actually are...

I personally have never experienced any problems with the all-wheel drive system.

Best regards.
Jan.

linklon wrote:

I have driven it for the last 20,000 km. and it only caused problems... icon_evil.gif I don't know how reliable the statements of the previous owner are. actually are... I myself have never experienced any problems with the all-wheel drive system.

Okay, just decide on one thing. Have you had problems with it for 20,000 km, or have you never had any problems with the all-wheel drive ?

Take a look at the pump's connections.

Sorry... I probably didn't express myself clearly.

I haven't had any problems with the all-wheel drive so far, but...
Otherwise, I had a few minor problems with the car.
like crankshaft bearing damage, misfires, etc.

I will take a look at the pump's connections... thank you very much.

Best,
Jan

I checked the connector of the pump that connects to the Haldex control unit.
Next, I checked the cables where they disappear into the pump.
"The probe is activated, and the pressure at the pump is being monitored. The 'Pre-charge pump on' menu option is selected."
measured during actuator diagnostics. -> 4.2V, which is probably a bit low...
The pump has a resistance of 2.5 ohms, which seems reasonable to me.
Even when measuring the resistance at the connector leading to the Haldex control unit, I get 2.5 ohms.
Therefore, I believe I can rule out the supply line to the pump as the cause.

Should I now replace the Haldex STG (hydraulic unit) or the pump?

I've been thinking about the following:

If the pump draws more than 2.58 amperes, as indicated in the actuator diagnostics...
displayed in the menu under "Pre-charge pump on"), pulling may indicate a faulty Haldex control unit.
I'm also not sure how much I can trust the power readings from a control unit that might be malfunctioning.

If the pump is not allowed to draw more than 2.58 amperes.
and the Haldex STG had a current limiting function in its output.
"The 4.2V reading seems plausible, and it's likely that the pump needs to be replaced."

Please correct me if my assumptions are wrong.

Does anyone know how much electricity this pump typically uses or is allowed to draw?
(Is the information visible in the third box within the actuator diagnostics?)
Menu item: "Turn on pre-charge pump".

Can I directly connect the pump to 12V to see if it starts working?
Or could something break in the process?

Here's what I have installed:

Address 22: All-wheel drive
Label file: RKS\1K0-907-554.LBL
Control unit part number: 1K0 907 554 C.
Component and/or version: HALDEX 4Motion 0108
Encoding: 0000001
Operating number: WSC 00000 000 00000
VCID: 2D5A657BB4D92870BAA

Best,
Jan

Error found!

Although I initially suspected the Haldex system, it seems that...
The pump may be the cause of the error.

I directly connected the pump to 12V, and for about 10 seconds, nothing happened.
...then, it was heard how she was slowly and reluctantly...
set in motion. The noises the pump made revealed...
It is quite clear that she wants to be replaced.

It seems that the outlet of the pump is indeed regulated.

After the experiment described above, I reconnected the pump to the control unit (STG).
And then, behold... it's moving...

When the pump is turned on, it briefly runs at a high speed and then slows down.

My broken pump draws 3.55 amps when powered directly with 12V.

Subsequently, the Haldex system was checked with diagnostic tools and the actuator was tested -> OK.

Best,
Jan

for resolution!

It all comes from pseudo-4WD drivers. They don't actually need all-wheel drive, and the rear axle is rarely or never used.

Then the parts will rot and will not be usable when needed.