C3 Pluriel Electronic nightmare!!

[myglaren]

I expect it was BB Reman you were thinking of. Closed in 2022
https://www.500eboard.co/forums/threads ... ing.17325/

[Paul-R]

Reading further into the link there is another company that can remanufacture what BB used to do.

https://remanx.com/pages/welcome-to-remanx

[AllanA]

Good suggestions. Thank you!

[GiveMeABreak]

Injection


ABS

[AllanA]

Still waiting for the replacement ECU to arrive.

In the meantime I decided to take out the battery , battery box and front left headlight so I could get easier access to the wiring, components and earthing points.

I wanted to check continuity between the ECU and ABS and all appeared to be ok EXCEPT on the CAN bus!

Each point I've checked so far has 124 ohms but I think I'm correct in understanding it should be around 60 ohms between CAN Hi and CAN Low. I've back probed at the following points:
OBD connector pins 6 (Can H) white wire and 14 (Can L) blue wire. EPS module twisted wires purple and beige. BSI has five twisted pairs that I could see so I tested between purple and green pair and got the same 124 ohms. I have continuity between the purple and green pair between the ECU and ABS unit but 0 ohms.

There's also another twisted pair to the OBD connector pins 3 and 8 where I also get 124 ohms!

So that leads me to believe there is an open circuit somewhere along the wires between start and finish of the CAN Bus.

Does anybody know the CAN Bus start and finish twisted pair colours or have a diagram that I can logically follow to find out where the open circuit is? There are so many different colour twisted pairs that I haven't yet been able to trace that link between start and finish.

Thanks in anticipation!

[wheeler]

Go to ABS ECU & with the unit disconnected measure across pins 19 & 25 then 21 & 23 of the harness connector. Each of these should be 120 ohms, let me know if this is not the case on any of these.
Also confirm the wires on these pins are twisted pairs.

The start point will be terminals 2 & 4 of the 40 way black connector on the BSI & the 'finish' will be terminals A3 & A4 of the 32 way black connector of the injection ECU.

[AllanA]

Wheeler, thanks so much for that info.

Today I checked out the CAN Bus wires from BSI to ABS, BSM, EPS and engine ECU. All checked out for continuity and I had 124 ohms across the pins you referred to and also at the OBD connector between pins 6 and 14. All were twisted pairs.

The replacement ECU arruved today so before I connected that I put the original one back in and ran Lexia. Well, I had more faults flag up than before!! So I installed the new ECU and ran Lexia. Having cleared the previous fault codes I ran another global diagnosis and to my surprise there were 0 faults. And further more the engine now turns over on key start position. Obviously it doesn't start because the ECU is from another car and not recognised by the immo. But at least I now have confirmation that the ECU was faulty.

So next thing is to figure how to get the ECU virginised. Can I do it myself or do I have to send away for that to be done? Anyone know if it's possible to swap out the eeprom?

[wheeler]

Has the CAN bus now dropped back down to 60 ohms with the new ECU installed as it should be?

[AllanA]

I'll check today before I start refitting everything I removed for access. Any thoughts on best locations to test? I'm thinking ign off, everything connected, back probe at ecu pins A3 and A4, abs pins 19 and 25 plus pins 21 and 23, pins 2 and 4 on the bsi. Also at the obd connector.

[AllanA]

CAN bus now reading 61.9 ohms :)

I've decided that what I'm going to do is desolder the eeprom from my original ecu and put it in the donor ecu which hopefully should enable the immo to allow starting.

I'll reseal the ecu case using Sikaflex 291 marine grade sealant.

[wheeler]

If you have an eeprom reader/writer might be worth trying to read & write the eeprom in circuit. Would be good to at least get a backup of the original eeprom in case anything goes wrong.

[AllanA]

Yes good suggestion. I haven't got an eeprom read/writer but was thinking of buying a clone xprog as it's not something I would be using much. Good to have a backup though so would be worth the reasonable cost.

[AllanA]

I'm thinking of buying xprog 6.12 or 6.50. Anybody have experience of these or other recomendations please?

[wheeler]

Never used Xprog, i use VVDI Prog & VVDI Mini Prog. Not likely to be worth it just to do one job though.
Plenty of cheap lits out there like UPA USB. Im not that confident with soldering though so just use clips for in circuit reading/writing.

[AllanA]

Thanks wheeler. Just had a look and decided to buy UPA USB Pro latest version which works with Windows 10. The main thing is to use for read/write eeproms ST19650.