Citroen XM Forum

I am currently working through the old engine management loom i have to see what the ECU plug pinouts are, nearly done but my pixy finder battery died on me before i could finish.
Would there be any value in writting this up and posting it to the self help section, i will also be doing the same with the later MK2 ecu as im interested in compatability between the two looms.

YOGs old loom is, well, old! corrosion is rife as is high resistance connections, im questioning my sanity in trying to save this loom but want the plug and play ability, the other loom seems ok after the same quick check BUT there are two blank spaces on the early loom and only 1 on the later loom, i need to make sure if i use the later loom all the smoke wont leak out of expensive and hard to replace things when i supply it with power for the first time.

If there is no interest i will take it no further than my encoded handwriting on grease covered bits of paper.

D

I have a Citroen workshop manual with wiring diagrams that include this information Dean and I am using it to try and pinpoint my issue! I noticed there are differences between my early and late ecu plugs in the blanks as you mention. Regards, Matthew T.

A pinout list would be good.

V6 launch engine wiring diagram. John

Here is another simpler version of the engine vitals with my annotations:

ecu - purple
power - red
ignition - blue
fuel - orange
relays - green
sensors - yellow

Hopefully the ecu pinout numbers may just be readable!

With regards,

Matthew T.

Hi Matthew

That is the 1505 version of the engine wiring diagram.
Do you know the correct colour code for the matching ECU.
The one I put up was from the booklet for the V6 launch.
In the main workshop manual there are quite a number of Fenix 3B wiring diagrams and colour matched ECU's.
R1504 - three versions/variations listed.
R1505 - nine versions/variations listed.
US83 - eight versions/variations listed.
The above is taken from the workshop manual index updates 12 & 15.

On that basis Dean's physical check of actual harnesses may be the best route for his needs.
Fenix 4 variants were the Citroen V6-24v ECU's.
There was also a Fenix 5 ECU which I think was for the Renault PRV's.

John

Right, new Battery for the Pixie finder and i can confirm the Loom must stay with the ECU, pinout differences between earlier and later harness' are substantial and so far i have found if i used the later loom on the only ecu i have then the ground to the front and rear knock sensor and blue canister purge valve would actually end up pinned into the signal from the O2 sensor, most of the pins are the same on the ecu plug but about 7 have changed places.

Also later cars had a much different chassis loom, it is do-able but for the effort involved v rebuilding the old loom and modifying my car harness by adding other looms i dont have its a waste of time.

The later loom is, in short, scrap without its ECU. I have no choice but to cut it up to provide all the replacement plugs i need plus some upgraded water tight plugs with better shielding for the old loom.

Time to get the soldering iron out! and pray the 4 digit keypad code written on YOGs keyring is the right one for the ECU because if it isnt i will be up poop creak without a paddle or canoe!! the keypad didnt really work on YOG so i could not check before it came apart.

Fingers crossed

D

Here is my list of the ecu connections after earlier explorations and I can confirm that the information is broadly correct for my 1990 model. Regards, Matthew T.

That is the 1505 version of the engine wiring diagram.

My diagram came from the Peter Russek manual John and seems broadly similar to the one you posted, although I confess have not checked all the detail. With regards, Matthew T.

That is the pinouts for the early loom the later loom with two blank spaces in the ECU plug is different.

Saves my writting it up, Matthew can you make an entry in the self help files with a good searchable title and post the wiring diagrams and ECU pinouts for future reference which will be easy to find.

D