Bosch ECU and Siemens ECU Interchangeble

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

esajoda
Posts: 12
Joined: 23 Feb 2024, 14:36
x 1

Bosch ECU and Siemens ECU Interchangeble

Post by esajoda »

I am opening myself to abuse :-D My logic tells me NO. ( Wish I had the knowledge of some of the people on this Forum, then wouldn't have to pose these questions)

I have 2 x 2004 C3 1.4 HDI 8v and want to get 1 perfectly working vehicle from them, here are their VIN numbers:-
VIN VF7**************[VIN obfuscated, can be read by forum staff] (engine and gearbox needs replacing)
and
VIN VF7**************[VIN obfuscated, can be read by forum staff] ( Donor engine and gearbox)

Both vehicle start and drive, the only snag is that the one with the perfect body has a motor that leaks oil and smokes plus gearbox only has limited gears,
so plan is to carryout Engine and gearbox transplant.

Can it be done
User avatar
GiveMeABreak
Forum Admin Team
Posts: 38206
Joined: 15 Sep 2015, 19:38
x 5934

Re: Bosch ECU and Siemens ECU Interchangeble

Post by GiveMeABreak »

I can't really advise as although these are similar engines 2004 and 2005, there are slight differences between the engines and the engine ECUs, but I can't advise of other differences.
Please Don't PM Me For Technical Help

Marc
esajoda
Posts: 12
Joined: 23 Feb 2024, 14:36
x 1

Re: Bosch ECU and Siemens ECU Interchangeble

Post by esajoda »

Thanks Mark, thiink I'm going to take the chance, its going to cost me around 600 pounds to purchase the vehicle, if it doesnt work then i bought a heavy paper weight.
User avatar
GiveMeABreak
Forum Admin Team
Posts: 38206
Joined: 15 Sep 2015, 19:38
x 5934

Re: Bosch ECU and Siemens ECU Interchangeble

Post by GiveMeABreak »

The only thing going in your favour that I can see is that the later 2005 vehicle you mentioned above, is still showing as the old style C3 before they updated it later in 2005, which has the CAN electrical system - which then probably would of caused you some issues with the ECUs and electrical equipment, being incompatible with the earlier version.
Please Don't PM Me For Technical Help

Marc
esajoda
Posts: 12
Joined: 23 Feb 2024, 14:36
x 1

Re: Bosch ECU and Siemens ECU Interchangeble

Post by esajoda »

Thanks again, remember seeing that it was sold in January 2005, think in service book, so its definitely a 2004 model only registered in 2005.
User avatar
GiveMeABreak
Forum Admin Team
Posts: 38206
Joined: 15 Sep 2015, 19:38
x 5934

Re: Bosch ECU and Siemens ECU Interchangeble

Post by GiveMeABreak »

No, the VIN ending in 455 is a 2005 model. It's build code is 10308, which means it was built at the factory on 28 January 2005. The revised C3 came out later in the year about October IIRC.

We don't use registration dates only build dates to determine the correct date.
Please Don't PM Me For Technical Help

Marc
User avatar
darbuck
Donor 2023
Posts: 1068
Joined: 25 May 2014, 16:45
x 150

Re: Bosch ECU and Siemens ECU Interchangeble

Post by darbuck »

You will need the bsi ECU injectors all from the same car either Bosch or Siemens ECU and injectors are paired to the individual bsi and the keys need to match as well or possibly the ignition barrel as well as long as you have all that you are good . They all just need to match. That's assuming the engines are the same.
Darren
esajoda
Posts: 12
Joined: 23 Feb 2024, 14:36
x 1

Re: Bosch ECU and Siemens ECU Interchangeble

Post by esajoda »

Thanks Mark& Darren, sorry to be a pain, from the VIN number can you see what ECU the car was manufactured with?
User avatar
GiveMeABreak
Forum Admin Team
Posts: 38206
Joined: 15 Sep 2015, 19:38
x 5934

Re: Bosch ECU and Siemens ECU Interchangeble

Post by GiveMeABreak »

455 Bosch
124 Siemens
Please Don't PM Me For Technical Help

Marc
esajoda
Posts: 12
Joined: 23 Feb 2024, 14:36
x 1

Re: Bosch ECU and Siemens ECU Interchangeble

Post by esajoda »

Thanks Mark.

Have just finished stripping the motor out of car I bought, let's say I'm not impressed with who ever worked on the car before, found some cut off wires so now contemplating replacing complete wiring harness from perfectly working donor car.
User avatar
darbuck
Donor 2023
Posts: 1068
Joined: 25 May 2014, 16:45
x 150

Re: Bosch ECU and Siemens ECU Interchangeble

Post by darbuck »

Well that sounds like a good plan given the ECU's and injectors are from different manufacturers, injector connectors are probably different and you might have different sensors on the donor engine which is why I alluded to swap everything engine and ECU related. It might take a bit longer but more likely to work without too many issues. You might find one has more or less auxiliary computers that you will either have to turn on or off in lexia as well or she will throw tantrums.
Darren