# CAN bus control of Volvo steering pump



## skooler (Mar 26, 2011)

I have done exactly this on my RX8's EPS system (electronic power steering). By this I mean that the rack is entirely electromechanical. - No hydraulics whatsoever.

Originally, the ECU sent signals to the EPS controller via CANbus (Vehicle speed, engine RPM etc.)

With a '0' value for engine RPM being received in the CAN messages, the EPS controller wouldnt function.

The solution was to cut the wires between the ECU and EPS controller and join to my own controller, which sends the messages the EPS controller needs to receive in order to function.

Finding the messages is relatively simple. you just need some CAN sniffing software and some common sense to filter out all the crap (using a working ICE car). Then simply recreate the message and stream it to the EPS controller over the bus. Use you preffered microcontroller package Arduino being the most obvious choice...

In addition, if you want to control the amount of assist, you just need to let the micrcontroller know the vehicle speed and output the appropriate message based on that speed.

Hope this helps.

Cheers,

Mike


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## mx6 (Dec 8, 2010)

Basser I am in the same wagon. I got an S40 Volvo Pump. I also need the connectors. Did you get any more info?

Alex


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## flightrail john (Feb 10, 2011)

I just rec'd a TRW pump. It has two large terminals and three small pins. Can anyone post a diagram of the pinouts? There are no labels and I do not have plugs or wires. I wouldn't want to connect the power in to wrong polarity and the case is really well sealed up.


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## rod19033 (Nov 24, 2021)

skooler said:


> I have done exactly this on my RX8's EPS system (electronic power steering). By this I mean that the rack is entirely electromechanical. - No hydraulics whatsoever.
> 
> Originally, the ECU sent signals to the EPS controller via CANbus (Vehicle speed, engine RPM etc.)
> 
> ...


Hi Mike
Good article thanks

Can you give me the can commands you figured out please? I can't find a volvo to get my hands on to log.
Thank you


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## Nmstec (4 mo ago)

rod19033 said:


> Hi Mike
> Good article thanks
> 
> Can you give me the can commands you figured out please? I can't find a volvo to get my hands on to log.
> Thank you


We recently released the information online for free, as well as have a built solution.

NMSTEC/Volvo_EPS_FREE (github.com) 

Universal PSC/NMS-PSC – NMStec


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## rod19033 (Nov 24, 2021)

Nmstec said:


> We recently released the information online for free, as well as have a built solution.
> 
> NMSTEC/Volvo_EPS_FREE (github.com)
> 
> Universal PSC/NMS-PSC – NMStec


thanks very much!


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