# VW servo pump pinout



## steven4601 (Nov 11, 2010)

Hello,

I just bought an electrical servo pump for the power assisted steering. However I seem to be unable to find actual wire diagrams for the pump. Input would be very welcome.

Its from a 2009 Volkswagen Polo. Pump brand is TRW, type number 6R0423156. The unit has three connectors. from left to right having: three, two and four connections. 

I have 2 of the 3 connectors that apear to be intended for these kind of pumps. Also found the/a third connector that fits for the 3 pin connector but I found it somewhere in different car.


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## steven4601 (Nov 11, 2010)

Maybe its obvious for VW experts but this is a CAN based puppy 
And it is not pumping apearantly without being commanded to.

However, this is what I have found out by probing around and carefully applying voltages:

Only 12V to the power terminals makes it draw less than 1mA. 
Also sending 12V to the Ignition signal raises the power consumption to ~ 50mA. The Pin 7 starts feeding 12 volt also, but not from the IGN wire but from the Pwr terminals. Pin 9 is weakly pulled up to 12 volt too. I think this is for the steering rack angular rate signal..

Im stuck with the CAN signals atm., I can see the 1V differential signal on the scope, but do not have a CAN analyser nor do I know what to send back to make it wake up. ANd worst of all is the chance that it is locked out due to a crash. Read about TRW drive pumps being able to remember/detect a crash and shut of entirely until the vehicle is serviced with diagnostic tooling.... . 

Not so bright move of me buying this unit.


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## Peter S (Mar 5, 2009)

The unit needs a cansignal that the ice i running ,it wont start without it

The steerangelsensor tells the pump to increase pressure fast (depending of speed singnal from abs unit

Without steerangelsensor the powersteering will be hard to turn for the first half second before the pump compensate for low pressiur,thats why it increace pressure when it notis movment from the seeringrack ( to save amps)

It takes a lot of amps and thats why its not allowed to start without ICE turning the alternator

I have the pinout at work and can post it tomorrow if you still want it


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## jackbauer (Jan 12, 2008)

One option (though not ideal) is to cut open the terminal box and toss out all that nonsense control gear and go direct to the motor terminals. The other option is to go with the ubiquitous mr2 pump. I've been running one for over a year no problems. Only draws heavy amps when on load.


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## Peter S (Mar 5, 2009)

I have been thinking about this too,but I afraid that the pump will draw alot of amps and overheat.

When the steeringanglesensor breaksdown on a Polo the customers goes to our workshop and ask why the halfbeam blinks up and down and its due to powersteeringpump going up and down in pressure


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## steven4601 (Nov 11, 2010)

Hi Damian and Peter

Gutting the control electronics is my last resort. It needs a Brushless dc controller. I have a few 150A controllers laying around but that makes this unit quite expensive. Paid 200,- for this unit. Adding a 80 euro controller makes no sense. I may look into returning this item if I cant find the CAN commands.

Hi Peter,
The exact pinout would be very nice yes. Also do you have the CAN memory locations & details? I found 0x3DE and 0x5DE hold status and failures but dont know the data format or length. Also is there a way to reset these units after a crash? I read that they remember crashes and disable them self. ?

EDit: does it NEED oil to run at all? low level detection/Protection? Or can I test it spinning up without oil?


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## Peter S (Mar 5, 2009)

I dont think it will remember the crash, I have mounted a used unit from a crashed car last week and I only have to change the variantcoding ( donor car had ESP and the otherone dont)

No oilsensor but it wont last forever without oil

It can stop if B+ is low or CAN signal "ICE not running"

If you use a dc controller you will still have the stiff steering problem before it notis the pressuredrop/motorrpmdrop


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## steven4601 (Nov 11, 2010)

I think I need the 'engine running' signal then 

Do you have command/can data what to send to the unit? I guess it is constant/periodic data.


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## Peter S (Mar 5, 2009)

4 pin connector
1 CAN Low
2 Can High
3 Empty
4 Ign (+15)

2 pin connector
1 B+
2 Ground

3 pin connector
1-3 steeranglesensor


I dont have the commands,on my evpolo I let the ICE controlunit think that the ICE is spinning by feeding the CKP sensor


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## steven4601 (Nov 11, 2010)

Thanks,

The steering wheel connector is 12V for the electronics, DItto for the GND signal and the weak pull up 12V is the PWM input for how fast the pump should turn to keep the hydraulic pressure constant. Pretty straight forward.

CAN is rather proprietary. 
Im going to search for the CAN packet that is required to enable the pump. 
Let's make this a contest, who's going to beat me finding the required packet data


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## brainzel (Jun 15, 2009)

I had the same pump last year to be fitted to my VW new beetle.
It didn't work.
Personally I had no idea so I got help from a guy who worked for a VW dealer.
He pluged in a laptop with a software and tried to connect to the pump by can bus. But it seems that the gar and the pump uses another can bus signal.
After three days of trying and some weeks of searching, I decided to sell the pump (you will get your 200,- Euros minimum at f.ex. ebay) and bought another pump.

The Pump that fits to my car was out of an "Opel Astra G Caravan" and it's been manufactured by "Delphi" I think.
This pump has a 12V +, 12V- and a switched 12V+ (originally feeded from the alternator). I tunr on the car and the pump start to build up the preasure.

Everything works great since ~2500km/1500mi.

btw: don't run these pumps without liquid


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