Citroen XM Forum

The original V6 (SFZ) ECU at launch (23 Mai 89) was part number 96 033 117 label Blanc Vert Bendix 5 101 700 101.
This component is also listed for the UK launch (29 Sept 89).

John

That is odd Dean because the BVA definitely gives me a lower idle speed! Thanks for the interesting info John and do you also have details for other later ecu? With regards, Matthew T.

The Seimens Reference number tells all:
S 101 700 101 = V6-BVM.SFZ - J - Green 4/3/90
S 101 700 201 = V6-BVA.SFZ - E - Yellow 29/4/91
S 101 800 101 = V6-24.SKZ - K - Pink 18/2/91
S 101 700 102 = V6-BVM.S6A - C - Blue 5/9/90
S 101 700 202 = V6-BVA.S6A - D - Violet 3/11/90
The V6 ECU's are interchangeable.
The V6-24 has a wiring change for version K so check the mod.

John

MTXM wrote:That is odd Dean because the BVA definitely gives me a lower idle speed! Thanks for the interesting info John and do you also have details for other later ecu? With regards, Matthew T.

Would traditionally expect an auto to have an idling speed slightly higher than a manual, to prevent stalling/shudder when D is engaged - typically +100rpm. However, ECUs continuously monitor engine speed, and would simply increase idle speed to compensate for drive engagement.

In your case, Matt, wonder whether the ECU might have had its idle speed adjusted (I presume this is possible via Lexia) at some point?

Hi Matthew

Those details are all that I can find from the present searches.
There was a big change in ECU's when the V6 engines were revamped in 1994.
Are there any manufacturing dates on the two ECU's you put up photos of earlier in the post.
Your manual BVM one is software version K so introduced later than March 1990, colour coding seems to be white.
Your auto BVA one is software version E so code content dates from April 1991.
The Seimens reference number changes with each engine variation (SFZ = 101, S6A =102).
The software reference letter is specific to each Seimens reference number.
As the code is modified so the letter increments.
The earliest use of the ECU's probably went through quite a few development letters before car/engine launch.
That probably explains why most 101 BVM ECU's are version H, J, & K.
Later engine variants would need far less development software changes to reach production, so much earlier version letters.

John

Hi Chris

With the Fenix ECU there is no provision to alter idle speed setting using diagnostic tools.
Setting tables are hard coded into the ECU.
Standard idle speed is 750rpm (XM1 no.1 page39).

John

Many thanks for that further helpful info and comments John and Chris and in response to John I do not recall seeing any dates on the ecu. The auto is a 1990 model year car although the ecu may not be original and the manual was a 1991/2 estate. With regards, Matthew T.

Standard idle speed is 750rpm

That is interesting John as my 1990 auto is almost spot on this figure, which I thought was a little low! My other cars idle closer to 850-950rpm. With regards, Matthew T.

A low idle speed is desirable in auto form, to reduce "in gear creep".

Yes Will I can see that does make sense! Regards, Matthew T.