Citroen XM Forum

I think I have now found the problem with the ecu chaps as there are a couple of wires on the back of the circuit board that have obviously been hot and one is broken. Hopefully I can solder in a new section of wire to bridge the gap! Regards, Matthew T.

That track has obviously got a bit hot. Check the surrounding components to see if any are burnt.

There are no other signs of burning or damage Will including to components and it seems to be just the burnt out track causing a poor connection. I have now affected a repair although it is yet to be tested! Regards, Matthew T.

If the burnt track are ground tracks (it looks like they might be), then this type of burning is often caused by a defective engine ground cable, causing some of the starter current to be routed trough the ECU, which is not really designed to handle it. Other grounding issues can cause similar issues.

Second that. Well spotted, Matt.

I do not think there have been any problems with engine earthing Mike and I had assumed that the damage has arisen through an erratic signal from the crankshaft sensor, since the ecu connection is certainly part of that circuit. Regards, Matthew T.

I just wondered if anyone could provide definitive advice on the V6 12v Fenix 3 ecu and the various known types and compatibilities? As I recall there was an earlier post by John on this subject that I could try and track down. In a more recent thread Dean referred to the auto having a white label ecu, although my 'G' reg. car has a yellow label, which I assume is original? My photo show two examples that I am using happily on my 1990 auto. The very early Poland car engine and suspension ecu certainly do seem to be different and are not interchangeable with other models I have found. Regards, Matthew T.

The ecu on the right is a manual one BVM (manual), the BVA (Auto) ECU probably has a lower idle speed and other trailing throttle fueling map differences to improve fuel economy and other features that improve driveability.
As you know later ECU's are pinned differently than early ones so not interchangeable, other than that i dont know.

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Thanks Dean and that makes sense as the yellow label ecu is original to the car. The manual ecu must have come off the estate car I broke and there was no noticeable different to the running fitted on the auto. If anything the BVA ecu gave the lower idle speed. With regards, Matthew T.

the BVA should give the lower idle so as not to load the Torque converter too much when in gear stationary. also gives a smoother shift into gear.

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