2009 Avant A4 Servotronic relay location

[sannouni]

Where is the Servotronic relay on a 2009 Audi A4 Avant Automatic ??

forums and google search results pointed to someone with exactly the same problem I'm having (link below) ... fast facts:

the steering servotronic unit was working perfectly fine until i took the car to have the pistons changed for the oil consumption known issue... (aftermarket garage)

when i got it back, the steering was heavy, then i checked the codes using VCDS and got (02838 - solenoid Valve For Servotronic (N119) Electrical Fault in Circuit), when i delete the code, the steering immediately comes back to expected behaviour (light when stopped and heavy when on highway speeds, etc.)

When starting the car after a cold soak (few hours or overnight) the steering gets heavy again... the same code returns. however, if the engine is at normal operating temp for a while, and the ignition is cycled, the servotronic unit starts working again.

I read online that Relay 640 might be the problem (Actually the problem i'm facing is exactly the same as this: ( https://www.audi-sport.net/xf/thread...rnings.167259/ )

I've searched online for a diagram to locate the relays, but i havent found relay 640 yet on the station wagon...

I removed the knee panel and searched for the relay (following the write ups/mod to make the steering heavier on purpose, i.e. cancel the Servotronic Function), but was unable to find a #640 there... am i missing something? is it not there because it's an avant? if so where would you advise for me to look?

Thanks a million !

[Gunnark100]

This sportnet thread is about b7 not b8. As for b8, cant see any relay for steering on diagram.
N119 is connected directly to J519(BCM01)

[sannouni]

Thanks Gunnark100
now that i'm back at square 1... any hints on what i should look for ?

[Gunnark100]

Thanks Gunnark100
now that i'm back at square 1... any hints on what i should look for ?

Take a look here, should get few ideas...
https://www.audizine.com/forum/showt...ing-on-and-off

[sannouni]

Thank you, i took a look at it, went to the car to inspect the area where the Universal joint is (for the steering column) and sprayed it with lubricant, but it did nothing to remedy the problem...

The garage had to empty out the steering fluid when taking the engine out... could it be that they filled it back up with the wrong fluid?

would it be possible that the N119 wiring harness was removed during the engine install and is not pushed back in all the way or is contaminated (is it even accessible from the engine bay?)

Why would the system immediately normalize as soon as the code is deleted (02838 - solenoid Valve For Servotronic (N119) Electrical Fault in Circuit)?

[sannouni]

went to the car again and noticed that the plug that goes into the solenoid has a broken latch (that extra piece of plastic that makes it easy for a human hand to disconnect the plug) so i knew someone has at least attempted to open it... then decided to disconnect and clean the connector... it took a lot of patience, but it was done... waited for a cold soak again (temperature around -10C), and the problem is still there... when it warmed up, i need to cycle the ignition for the solenoid to kick in again...

before plugging the connector back, using a multimeter, the voltage across the connector jumps to around 7V for a split second (when the ignition is on), then drops back down to zero... not sure if this is a normal behaviour or not...


generally speaking, is there a fault with those solenoids? ... do they become defective with time? and would the solenoid from a B7 fit? (according to ECS tuning parts search, it seems to fit)

Is there a write up/DIY on changing the solenoid? i couldn't find any.

[sannouni]

Update... when tapping the solenoid with a wooden stick prior to a cold start, it seems to function. so now, the culprits are narrowed down to: (feel free to add something if you think needs to be considered):

• The solenoid itself
• Something (debris) interfering with it's function (the fluid was removed when the engine was taken out, and later topped up by the garage)
• The type of the fluid used may not help the solenoid function properly until it's warmed up
• The voltage supply to the solenoid at startup

start with the cheapest and work the way up.

1. free: check the fuses (highly unlikely that i'd find something wrong)
2. cheap: perform a flush of the fluid, using original VW/Audi Fluid hopefully dislodging whatever is making the solenoid stick when cold
3. expensive: change the solenoid and cross my fingers that it remedies the problem.

[sannouni]

Update: to anyone that has the same issue and that had the engine taken out for repairs recently..
I tried cleaning the connector and flushing fluid. No change was noticed. It was happening randomly, but the only thing that was somewhat consistent was that it would come back to life when the engine is warmed up to operating temp. I even doubted that the alternator was providing enough voltage... and it actually, strangely wasn't. But even replacing an alternator fix the heavy steering....
I decided to track the wiring coming from the plug all the way to the electrical system main box. Tested the resistance at the solenoid, and found it to be around 7.4 Ohm. STRANGELY, all wire continuity checked out fine, but when it came to voltage (turning on the ignition powers the connector to the solenoid) no voltage was coming in to the solenoid connector (which makes me think that some bare wires are touching somewher)
I cut and spliced the connector wiring from the servotronic solenoid to the intermediate connector that's found in the ECU box next to the brake fluid reservoir, under the washer fluid fill port (https://goo.gl/images/Q4xXsm) (I used this for reference on how to access the ECU box https://www.audizine.com/forum/showt...stallation-DIY)

The problem was resolved since. However, the wires that remain (the damaged wires) can still cause problems later, in other ways, because if the conclusion is correct (bare wires touching somewhere in the conduit where the original solenoid wires are routed) the only way to fully remedy the issue is to either trace all wires in the conduit to see which other one is causing a problem, or to replace the wiring harness that the servotronic solenoid connector is part of)
I used the pictures that are in following link )