DIY ECU tuning for Motronic 4.4 (pre-99 X70s)

Hi Guys,

One of the things I love doing on my C70 is modifying the ECU. I have learnt a lot about my car this way, and had heaps of fun doing it.

There is a really good thread (albeit large) here and a great Wiki (relate to the site) here

These both have all the information that you need to flash your own ECU, and I do not take any credit for any of the work. Also, I suggest that these be your primary source of information. I just wanted to create a thread to give some local help on the forum, and to spread the word! Especially when many seem overwhelmed by the hundreds of pages on VolvoSpeed.

Modifying the ECU
First you need to mod your ECU. This is not as hard as it seems, all you need to do is be able to temporarily join two pins (to activate flash mode).

Pry the little tabs back,

and fold the lever arm around over the heat sink formations. (little force required).

Identify the pins that you are going to join, namely A12 and B8.

You will have to bend the pins around A12 to get to them.

I just soldered a switch between the two and installed it in the top of the ECU, but if you are just going to flash once, just solder a wire directly between the pins and remove it later.

Building a Tune
Download the 607 or 608 binary from the wikia, and open it in tunerpro (together with associated filed).

There are heaps of parameters that you can change. You will probably need to change the injector constant to match your injectors. I would suggest getting a basic tune running on your car before you change timing or up the boost.

When you want to play a little more, you might want to adjust the fuelling (particularly if you have a wideband), timing, and boost.

You will notice most tables have a load axis. Load is related to fuel and air going through the engine. More boost at a particular RPM generally correlates to more load at that RPM (in very simply terms).

Logging is one of the best parts of a DIY flash in my opinion. You can see so many apsects of your car.

Note that the engine is started, so the values are way off. But you can record a trip on your car and play it back later.

If you get hooked (like I did) and want to do more substantial changes to your car, I suggest buying a wideband 02 sensor (so you can adjust your fuelling properly) and a pressure sensor.

Note: This is just a brief introduction, and isn’t standalone. I just want to spread the word and get a local discussion going. You will have to do your own reading and download some software from the wiki and elsewhere, buy a $20 cable and set it all up. You will also need a good battery charger (or be able to add further electronics to your ECU) to be able to flash in car.


  • PS, dont tell my wife that I was working on the dinner table when she was out...
  • Vee_QueVee_Que @Vee_Que South Eastern suburbs Melbourne.
    Love it! The program looks similar to ls1edit!
  • RaebirdRaebird @Raebird Collingwood Park, Qld.
    Great write up! Is motronic 4.4 used in everything from 850 onwards?
  • Great write up! Is motronic 4.4 used in everything from 850 onwards?

    Thanks. Not quite, early 850s have Motronic 4.3 (which can be converted to 4.4 easily) and late (99+) vehicles went over to ME7. And only turbo models (I keep forgetting that people buy non-turbo volvos :P )

    If I had an early 850, I would definitely convert it as it opens up the possibilities, and is really fun! For example, I converted mine to E85 with little effort (as have many), have removed the rear 02 sensor check, and switched off a few other silly features.

  • Ex850RSnoopy @Ex850R Somewhere Over the Rainbow. Melbourne.
    What did you turn off?
  • I cant remember exactly (and I am not in front of my tuning laptop), but at least the overboost cut-out, the whole rear 02 check, and the torque limiter. I did all of that about a year ago now, so it may be more. All I play with now is fuelling (with my wideband), load/boost, and timing.

  • Ex850RSnoopy @Ex850R Somewhere Over the Rainbow. Melbourne.
    I have a tune already , will this leave it on there and i can play with the rest or better to do a spare ECU?
  • No, flashing will write over everything. It should be easy to find a spare ECU, all turbos have identical hardware so any one will do.
  • RobRob @Rob - Lockyer Valley, SE Qld
    edited March 2015
    What is needed to convert a 4.3 car to 4.4?
  • I have never converted 4.3 to 4.4 before (and therefore not followed the discussion), but I believe it is straight forward, almost plug and play. If you have AC, you need to do a small mod to the ECU (or now even potentially just the ECU software - not 100% sure), but apart from that I think the harness, ECU plug and everything else is identical.
  • jamesincJames @jamesinc Oz Volvo Ice Fortress
    +1 great writeup
  • jamesincJames @jamesinc Oz Volvo Ice Fortress
    @Rob it is a direct swap from 4.3 to 4.4, but as @clinton said you need to address the A/C, but you can in fact do it in software. See this guide:
  • Ex850RSnoopy @Ex850R Somewhere Over the Rainbow. Melbourne.
    I would love to see what the tune i have has modified and apply that to a COP tune as well....
    @Rob‌ i expect your AWD has 4.4 as the othere turbo 850s did? Well , the R was a 'version' of 4.4 they say , probably an early itteration.
  • jamesincJames @jamesinc Oz Volvo Ice Fortress
    My 1996 850R is ME4.3. Now I need to find an ME4.4 ECU :<
  • nickmnicko @nickm Sydeneee --- home of the traffic jamb, over priced coffee, and the 2000 Olympics
    For the 850 R we need to work out the ECC hack. None of the V70 T5 you had still have it? Can we use a NA one?
  • NA wont work unless you do some soldering which I dont suggest. You should be able to find a turbo ECU reasonably easily.

    I think that Piet on the VolvoSpeed forum had a software fix for the AC mod recently, have a look at the most recent pages of the Tuners Rejoice thread. As mentioned, I have largely ignored it as I have a 98 C70.
  • @Rob‌ you would be wondering about converting the C70 yeah?
  • Rob's C70 will already be 4.4. The new AWD 850 might be 4.4 (I dont know, those things are so rare), otherwise it will be 4.3 so a perfect candidate for an upgrade.

    One of the good things about the DIY tune is the logging. It can help you identify problems with your car that you didnt know about. For example, my car was initially knocking - which resulted in timing retard and extra fueling. I was able to get rid of that by adjusting the cam timing.
  • jamesincJames @jamesinc Oz Volvo Ice Fortress
    For the 850 R we need to work out the ECC hack. None of the V70 T5 you had still have it? Can we use a NA one?

    I only had one, it was a manual and I sold the ECU to @Rob!
  • nickmnicko @nickm Sydeneee --- home of the traffic jamb, over priced coffee, and the 2000 Olympics
    does @Rob have a spare to play with?
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