General: 850: 850R ECU swap

[borb12]

Hi all,

I have a remapped ECU in my 850R Manual. I have a 850R auto ECU as I want a option to fill up with standard fuel. My problems is when I put the automatic ECU in it tries to start momentarily and then keeps cranking. When i swap back to the manual ECU fires in to life.

[volvo again]

doesn't a new ecu have to be programmed ??

[sda2489]

Pretty sure auto ECU doesn't work on a manual car.....

[sda2489]

See table

[PNuT]

immobiliser

Most modified 4.3 ecu's remove the feature of needing the immobiliser so if you are adding a stock ecu it will need it....

[borb12]

Thank you all for your replying. The table of ECU compatibility was useful.As my car is a 850r manual it does look like you can Bosch 0261 204 134 in it unless I'm reading it wrong. My thoughts are it is the immobilizer, would I need to get it reprogrammed at Volvo or is there a way to fool ECU to get a start signal?

[PNuT]

The immobiliser is not linked to the ecu so shouldn't need programmed, it is probably not getting a signal from the key to the immobiliser.

The other thing to consider is you may have a very late model 850r running motronic 4.4 as I seem to recall a few of them exist and you may be trying to run a 4.3 ecu on it....

[borb12]

Thanks PNuT,

I need to look to see if the key is communicating with immobilizer.What I do know it was a 4.3 ECU on my car from factory not 4.4. Unfortunately. Must have been a bit later when they put the 4.4 ECUs in, mine was registered February 1996.

[PNuT]

It isn't that difficult to switch to 4.4 and an ecu isn't that hard to get hold of and you could flash a manual T5 map to it.

Or get someone to do it for you

[winsox]

Originally Posted by PNuT

It isn't that difficult to switch to 4.4 and an ecu isn't that hard to get hold of and you could flash a manual T5 map to it.

Or get someone to do it for you

Dont plug an unmodified 4.4 into yours if you have a 4.3 in it.

It will Fry the Aircon .

An auto ECU will work in a manual but not the other way round.

If you run an Auto 4.3 in your manual you will find it very jerky on and off the accelerator ..been there done that and have the damaged engine mounts to prove it !