Power Steering stiff/hard - Servotronic?

[vtraudt]

The steering on this 2007 S6 needs a LOT of effort/force.
Reminds of the mod on the C5 when pulling the Servotronic relay for those who felt it was to soft (overboosted).

Does the C6 have a similar system (variable power steering assist)?

How the trouble shoot? Will scan with vagcom today (not sure if there is a power steering module to scan).

Is there are relay or fuse for the 'steering assist' system?

[Capt. Obvious]

Is it making any noise? Have you checked the fluid level?

[vtraudt]

Fluid level is good, no noise, no leak.
It is not as stiff as when power steering is NOT working.
Just much less boosted than normal.
On C5 generation A6 we sometimes pull the Servotronic relay because some find it too much assisted and prefer firmer steering (but a bit much at low speed without the relay).
D3 is obviously now more sophisticated, but still uses a valve. Just not sure if the solenoid is right on the rack, and how to troubleshoot it.
Can the solenoid be reached with driver side wheel off, fender liner off (or 'access panel' removed) to get to connector through wheel well?

[mkv]

Check if there's any faults for the servotronic valve. On a C6 it's driven by the central electronics or central electronics II unit. (so check for faults on that)
If there are not faults for it electrically, then it's possibly a faulty valve. It's mounted on the power steering box, i.e. the area of the rack where the steering column connects. It's held in with two very small bolts. If it's faulty or unplugged, it makes the steering very heavy on idle.

[vtraudt]

Check if there's any faults for the servotronic valve. On a C6 it's driven by the central electronics or central electronics II unit. (so check for faults on that)
If there are not faults for it electrically, then it's possibly a faulty valve. It's mounted on the power steering box, i.e. the area of the rack where the steering column connects. It's held in with two very small bolts. If it's faulty or unplugged, it makes the steering very heavy on idle.

Thanks, scanned the whole car, and as you suggested found code below. I assume the valve/solenoid is on the rack itself, driver side. Is it accessible (jack, wheel off, liner or cover off, reach in from the side?) to clean? Electrical test? Can the valve be bypassed (unplug, put permanent power to it)? DIY how to replace?

Or can car be softcoded to delete variable assist ("Servotronic")?

[mkv]

Which code did you find? And error for open circuit to the valve?

It's on the rack. See a photo here and google photos of 4F C6 steering racks.

I'm not sure if it can be replaced without removing the rack, but I think it could be. I had an issue with the wiring on mine, and I was able to remove and replace the plug to it. The previous owner had the transmission overhauled, and the shop who did it messed the wiring up to it. I replaced the wiring all the way from the module behind the glove box to the valve on the steering rack.

You can probably also test if for continuity and resistance, but I don't know the correct values off hand. I can check in Elsawin later on.

I don't think you want to put permanent power to it, the steering will be way too light at speed. I'm not sure if on a C6 it can be coded out, but without it functioning the steering is super heavy on idle, as you're aware.
It's just two wires or the valve which is at fault. Relatively simple cheap fix. Worth doing instead of trying to bypass. If the valve is dead, and replacement valves are pricey, you could even buy a whole second hand rack with the valve on for not much money. You have the power of eBay on your side. I'm not so lucky.

[vtraudt]

Code:

Wednesday,17,April,2019,11:16:55:03761
VCDS Version: Release 18.9.1 (x64) Running on Windows 7 x64
www.Ross-Tech.com

Address 4F: Centr. Electr. II Labels: None
Part No SW: 4E0 910 280 A HW: 4E0 907 280 B
Component: ILM Beifahrer H11 0070
Revision: Serial number: 00000000001500
Coding: 0010111
Shop #: WSC 02313 785 00200
VCID: 1E32539FC9B964BACF-804A

Subsystem 1 - Part No: 4E0 910 511 A
Component: UGDO HL US H04 0050

Subsystem 2 - Serial number: 0253440T1BKA05

1 Fault Found:
01797 - Power Steering Hydraulic Pressure Valve (N119/N315)
009 - Open or Short to Ground
Freeze Frame:
Fault Status: 01101001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 172
Mileage: 160016 km
Time Indication: 0
Date: 2019.04.17
Time: 11:07:00

[vtraudt]

Which code did you find? And error for open circuit to the valve?

It's on the rack. See a photo here and google photos of 4F C6 steering racks.

I'm not sure if it can be replaced without removing the rack, but I think it could be. I had an issue with the wiring on mine, and I was able to remove and replace the plug to it. The previous owner had the transmission overhauled, and the shop who did it messed the wiring up to it. I replaced the wiring all the way from the module behind the glove box to the valve on the steering rack.

You can probably also test if for continuity and resistance, but I don't know the correct values off hand. I can check in Elsawin later on.

I don't think you want to put permanent power to it, the steering will be way too light at speed. I'm not sure if on a C6 it can be coded out, but without it functioning the steering is super heavy on idle, as you're aware.
It's just two wires or the valve which is at fault. Relatively simple cheap fix. Worth doing instead of trying to bypass. If the valve is dead, and replacement valves are pricey, you could even buy a whole second hand rack with the valve on for not much money. You have the power of eBay on your side. I'm not so lucky.

Not sure if it is a solenoid or a mechanical valve. Solenoid would not work well (heat) with permanent 12V to it (100% duty cycle) if it needs power applied for 'high boost'.

Since rack is fine otherwise, obviously want to get by with the least amount of time and material invested. And chaning rack even on the C5 V6 is a PITA I don't want to deal with.

Passenger side/glove box: I assume that is where the 'servotronic' module is located, and termination point for the wires to the rack valve?

[stuffinder]

Responded on AW cut/pasted below
My '10 started steering really stiffly at low speed at about 115K. Checked fluid level OK but color wrong, flushed system w/fresh fluid ho help, installed new PS fluid reservoir as it's filter is integral w/res and no way to clean. New fluid of course.Still stiff for a few days & then cleared out and steering back to normal!

I never had any codes from Steering system on VAGCOM.

[mkv]

The problem is definitely something to do with the valve, cause you have the code for it. Either a wiring fault or a valve fault.

Elsawin states that the first operation to replacing the valve is removing the steering box, aka the rack. Now that doesn't mean that it has to be removed to replace it. Many times you can get to these things, it just may be rather tedious. You'll have to inspect yourself. IIRC the best way to get at it is right from underneath. You can't really see it, but you can feel it. From underneath the vehichle you have line of sight to the 18 mm adjustment nut on the base of the steering box, so with pictures of the rack off google you can work out where the valve is relative to that.

First check to see that it simply hasn't come unplugged.
Then I would remove the glove box and get hold of the connector from the electronics module II, find the two pins that the two wires to the valve are on, and check for resistance. If there is none, then chances are the valve coil has died. It's a solenoid valve. To confirm you can remove the plug from the valve, bridge the two contacts with a bit of wire, then check the plug side again.

I looked up your model's wiring diagrams. It says that it's two 0.35 mm wires, one brown/blue and one white/red. They travel directly from the module to the valve like that (one junction, but colours are the same.).
They are on pin 84 and 85 of the 40-pin connector to the module. Should be easy to spot them with the connector shroud removed.

[mkv]

Since rack is fine otherwise, obviously want to get by with the least amount of time and material invested. And chaning rack even on the C5 V6 is a PITA I don't want to deal with.

Ya, I more mean to just grab the valve off the second hand rack.

[vtraudt]

Thank you much, MKV! VERY helpful and to the point!!!