Hi, newbie with questions I'm afraid. My son-in-law has a 2013 Focus 1.6 zetec which has major electrical issues and won't start. it began when it snowed in January, one morning he went to it and the battery was dead. I went to it, checked with a voltmeter and it was reading under 5v. Fitted a new battery, starter worked fine but the engine wouldn't start, not even attempting to fire up. Checked on the internet, found out about resetting the battery management system, got the battery light to flash but still wouldn't run. By next morning the new battery was down to below 5v. Got the car recovered to an auto electrician who eventually diagnosed no signal to the fuel injectors because the engine ecu was blown. He was adamant that the battery polarity had been reversed (not happened) Also the fuse box had "water damage" on the C6 plug (engine) i.e. blackened and corroded pins and lacquer lifted off the circuit board. Got an ecu kit off ebay, supposedly compatible, nearly 3 weeks at the electricians to get it all fitted and working (ish). It's run fine for a week and then yesterday the battery was flat, swopped, reset battery monitor, starter spins but engine won't fire up. I've downloaded Forscan, found and cleared DTC's, most of which relate to not finding all the extra equipment on the donor vehicle, but nothing that seems relevant to the not starting. Quite frankly I'm not sure where to look next, has this happened to anyone else? I've tried to search the forum without luck, is there a go-to wizard with ecu's that anyone can recommend please?

TIA Pat

Welcome!

I'll defer to other petrol experts but if new battery goes flat overnight, you may likely have a parasitic drain that needs to be found and fixed (loads of videos on You Tube)
IMHO you only reset the BMS once when you fit a new battery.

Once that drain is fixed then it's again (?), back to fault codes/live data to see what is going on?
If ECU is definitely proven faulty there are companies that diagnose it but by the sound of it, you have had major electrical gremlins so wiring back to the ECU looks like it will need checking first.

However there's this:
https://www.ecutesting.com/common-faults/ford/focus-dashdashboard-instrument-cluster/

And:
https://www.ecutesting.com/common-faults/ford/focus-c-max-engine-ecu-fault/

Anyone?

Hi, thanks for the suggestions Shearers, I will go and check the dashboard lights, although none of the dtc's in either video have shown up on forscan so far. The auto electrician spent a lot of time checking the wiring and parasitic drains, although he never said what they were. The ECU kit was engine ECU, body ECU, dashboard, abs block and ignition switch. My last Ford was a Corrina so I have a lot of catching up to do!

Getting any battery drain sorted so that it doesn't go flat overnight is, to me, an obvious priority as it's never going to be reliable with that issue?

You can close all doors, trigger bonnet latch and lock car, wait 20 mins to let everything go to sleep then use a multimeter across fuses and a table that tells you how much current is flowing based on the mV drop across each size as a first try?:

https://www.powerprobe.com/na/en/product-list/content/www.powerprobe.com/resources/4Fuse_Charts_New.pdf

If you find any excessive circuit that doesn't matter then pull that fuse and try from there?

The donor modules need loading with the configuration for the car they are now fitted to.

For you to keep loosing the battery you have a parasitic drain that has nothing to do with any of the modules you've changed. This need repairing ASAP

You don't need to link the cluster with the PCM etc on Mk3, that's only MK2, you could've just changed the blown module, which I presume was the BCM

And, of course, the 2nd hand BCM could be water damaged in exactly the same place, did you check?

 The battery drain was sorted, for a week but has started again. That link to the fuse draw will be useful thanks. The electrician said the original ECU wasn't sending any message to the fuel injectors hence not starting, this time I have tried a squirt of Easy start which made no difference as though there's no spark. Can you mix and match ECU's and if they need coding to eachother can it be done with Forscan?

When I took the battery off yesterday there was about 35ohms between positive terminal and the body, so will be about 3amp drain. Cheers Pat.

1 hour ago, Pat Green said:

Can you mix and match ECU's

Yes

 

1 hour ago, Pat Green said:

and if they need coding to eachother can it be done with Forscan?

Yes

Coding is the important part, which all of your current modules will not be

Hopefully not raining tomorrow!