Replaced ECU, BSI and new key. Sill not starting, RAC says no comms from diagnostic port. Possible wiring issue.

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suavegarve
Posts: 10
Joined: 31 Dec 2020, 01:26

Re: Replaced ECU, BSI and new key. Sill not starting, RAC says no comms from diagnostic port. Possible wiring issue.

Post by suavegarve »

The fuses are all OK, and the plugs show no sign of corrosion. I'm gonna try a new fuse box anyway, as that's the last step before wires.

When you say same spec of vehicle, I can only find matching part number, but spec not listed. If the part number matches will that work in my vehicle.

Thanks for the responses so far.

citroenxm
Posts: 7888
Joined: 31 Dec 2004, 00:10
x 33

Re: Replaced ECU, BSI and new key. Sill not starting, RAC says no comms from diagnostic port. Possible wiring issue.

Post by citroenxm »

Yes as long as the numbers are the same on the bsm fuse box it be fine. .

suavegarve
Posts: 10
Joined: 31 Dec 2020, 01:26

Re: Replaced ECU, BSI and new key. Sill not starting, RAC says no comms from diagnostic port. Possible wiring issue.

Post by suavegarve »

Replaced the engine fuse box, and still nothing.

Must be a wiring issue I guess.

Where do we start?

wheeler
Posts: 4639
Joined: 21 Sep 2002, 19:07
x 212

Re: Replaced ECU, BSI and new key. Sill not starting, RAC says no comms from diagnostic port. Possible wiring issue.

Post by wheeler »

OK next step is to confirm that you have good earths at the following pins on the ECU plugs (with ECU disconnected)
48 way brown pins L4 & M4
32 way black pin H4
32 way grey pin H1
Also check there is a power supply to pin of pin B4 of the 48 way brown
You need to be really careful checking them as the terminals are really small & you dont want to damage them. Using copper strands from wire is more advisable to push into the plug than anything else or finley probing into the insulation of the wire as close to the plug as possible, if doing this you will need to re seal the wiring afterwards.

suavegarve
Posts: 10
Joined: 31 Dec 2020, 01:26

Re: Replaced ECU, BSI and new key. Sill not starting, RAC says no comms from diagnostic port. Possible wiring issue.

Post by suavegarve »

FIXED THE PROBLEM

Wire 1022 the red/white one that runs from the fuse box to the ECU, is apparently a known issue for problems. So I replaced it with a new wire and the car is now running perfectly.

Thanks for all the help received.

citroenxm
Posts: 7888
Joined: 31 Dec 2004, 00:10
x 33

Re: Replaced ECU, BSI and new key. Sill not starting, RAC says no comms from diagnostic port. Possible wiring issue.

Post by citroenxm »

Excellent.

Do you by interest have this on the fb 207 group too..?

suavegarve
Posts: 10
Joined: 31 Dec 2020, 01:26

Re: Replaced ECU, BSI and new key. Sill not starting, RAC says no comms from diagnostic port. Possible wiring issue.

Post by suavegarve »

Nope, don't use Facebook

mickeybo
Posts: 39
Joined: 14 Dec 2008, 19:45
x 1

Re: Replaced ECU, BSI and new key. Sill not starting, RAC says no comms from diagnostic port. Possible wiring issue.

Post by mickeybo »

The main control relay on these is a double relay which fires up the ecu at ign on and is earthed via the ecu via terminals 7 & 10 on this double relay. When this relay is working properly it fires up the ecu -fuel pump-& injectors & ignition coils Regards mickeybo