2005 Berlingo multispace 1.6HDI no comms with Engine ECU

[wildatsun]

Hi all , new to forum, got a few Citroens and Peugeots as I must like to tinker / fix annoying faults

I bought a non-running 2005 Berlingo multispace. 1.6HDI

The vehicle was working apparently until parked up for about a year.

Cranks but not firing.
OBD talks to airbag, display, dash, ABS but not engine ECU.

I have checked inside BSI. Perfect no corrosion. I cannot see any corroded plugs anywhere.
I have replaced the BSM fuse box under the bonnet. No difference.
I have purchased a complete set of components. BSI, ECU. cluster, RFID key chip and have changed all these units together.
Fault is same. No communication to engine ECU.

I have inspected the wiring harness (taken out inner wing liner and scuttle covers) and as far as I can see there is no problem / green copper, rodent damage or the like.
Not sure what to do next.
I am guessing either the ECU is not getting power or the CAN circuit is broken somewhere.

I have basic multimeter, test lamp. I could possibly borrow a scope, but i have very little knowledge of digital things, I am usually good with analogue electrical faults on old cars.

The car is in good condition and I really want to save it.
Thankyou! Will from Sussex

[wheeler]

First thing here you will need a wiring diagram for the engine management system then check all power supplies & earths are present. If they are ok you need to check the CAN lines for shorts to pos, neg & each other. A scope is not essential at this point but may come in handy.

If you provide your VIN somone may be able to supply the diagram.

[wildatsun]

thanks.
I did actually wonder if connecting a speaker to a can line would be a way to 'hear' if it was working, i don't know the data rate but maybe it would sound like a computer game cassette loading

[cancunia]

Just happened to be surfing the forum and came across this thread, looks like an interesting problem.
A 2005 car will be VANBUS as opposed to the later CANBUS, the OBD connector will be using various pins which may explain why some functions are there and some not, although the engine ECU should be on a common pin for OBD compliance. Perhaps first check the connector pins are all in place and not pushed through the back.
There's a thread I started on MHH Auto about the pinouts:
https://mhhauto.com/Thread-Looking-for- ... or-Pinouts

Might also be worth seeing if there are any friendly Lexia users in your area who could take a look. I think there's a list on here somewhere?

[wildatsun]

Thankyou annoyingly I am sure i have a lexia interface somewhere but I am not the tidiest person!
Port looks ok, I believe pin 7 is ECU. (top row, second from right)

[wheeler]

This car is actually VAN/CAN. The under bonnet stuff is CAN & the inside bits are VAN

[wildatsun]

OK progress.. of sorts.
I managed to grab an engine wiring harness off a scrap Berlingo, i plugged it into the ECU and the BSM (Fuse box under the bonnet) but left all of the other plugs disconnected (i didn't want to take the original harness out) and to my amazement the ECU came online and the diagnostics could talk to it perfectly. I unplugged the ECM plug nearest to the firewall, and still.. we had diagnostic communication. So i have kind of narrowed it down to this harness, and this plug (brown one at ECU) through to the black plug that goes to the BSM.

Unfortunately the spare harness has some wires cut from when the car was dismantled, so can't be used in its entirity but i could potentially make one out of the two if I can't find a decent replacement.

I have spent the last hour comparing continuity between the ecu plug and BSM plug and only 2 of the pins seem to connect (but same on both harnesses) which seems odd.

I decided to try and get into the ECU plug of the original harness to look for problems in there but they really don't like coming apart, full of some kind of sticky glue, and I couldn't get any pins out, but also pulling on the wires didn't cause any to break. BSM plug showing no corrosion or rotted wires.

I suppose there could be a short in the original harness, I wonder if i should strip it down .
I will post an update if i get anywhere, especially if I can find the actual cause.. as there's bound to be another car out there with the same problem and hopefully I can help someone else!

[wildatsun]

Ok . Newsflash.. There is a GREY wire which appears to be the EC relay trigger wire that runs from the brown (middle) ECU plug to the black plug in the underbonnet fusebox. I noticed when I touched the back of this grey wire in the black plug with the probe of a test lamp (grounded other end) the relay clicked and i could hear the various stepper motors and things on the engine wake up.

I spent a while trying to find where the break could be in this grey wire and gave up, I just soldered on a bypass from the ECU grey wire

to the fuse box grey wire.

it looks like wire has number 723755 on it


Started fine after that and diag comms with ECU.

Hope that helps someone else!

(Now to fix the other faults I've found including split heater core!)

[cancunia]

That's impressive! Thanks for posting the update & pix.

[Mel-ttn]

Thanks for posting, I have a 2007 multispace 1.6HDI here with same problem. Will check this.

[Mel-ttn]

Checked today and the same grey wire was corroded and broken contact.
All fixed and working now.
Thanks again.