I have been having the old charging fault on my recently purchased 2002 Mondeo 1.8 LX

I have the ECU and Battery light on after a few seconds of firing it up....

I checked the Alternator firstly, and it charges OK with the plug on the back unplugged, so assume thats OK...

I checked the loom and that seems fine (from the alt into the main harness)

I have noticed that someone has bodged a wire into the ECU that looks like its designed to knock the ECU light out - so am guessing its been messed about with st some point!

My question is - can I replace the ECU with another from the same engine/year?

If so, do I need the key and transponder from the replacement ECU?

Help!

 

I would start by having the fault codes read from the ecu. That might give a clue.
Then check whether or not this is an actual ecu problem, and if so check if the ecu can be repaired. Repairing might be cheaper than replacing, it is certainly easier.
Have you seen this: http://www.petercoopercarrepairs.co....t_charging.htm

When done properly on some makes, the ecu can be replaced by a second hand one.
I am not sure if that's the case here, but that would involve the help from a dealer or someone with Ford equipment.

 

Thanks for the link - I looked at that the first day the light appeared!

I am just looking at all options really - planning for the worst etc!

I am getting the codes read this week - bit I am sure it will say there is a charging fault! lol

 

Had an ecu failure on a friends mondeo.Got an ecu from ebayŁ40.Just make sure it has the same numbers on it as your old one.Then you need to code your old key to the new ecu.Ford charge Ł100 but i got a vehicle locksmith to do it form Ł40.Ł80 to fix the lot.

 

Ahhh OK, so its pointless buying a key/ECU/transponder combo if I can get mine coded? Was the locksmith a mate - do they need proof its your car etc?

 

Locksmith was a mate.Proof shouldn,t be a problem if it,s legit.All you need is an ecu with the same numbers on it as yours.Type the numbers into ebay search engine.
As suggested above,check fault codes first.Also check fuse 67 behind glovebox.(7.5amp)

 

Lol - yeah its all legit, have the log book etc. Is teh fuse box not under the bonnet then? I checked all those first!

What is 67?

 

2 Fuse boxes.1 under bonnet and the other behind gloce box.You need to take the glovebox out(just clips out.)Fuse 67 is for the ecu.They can pop and if it has ,it might have been bodged with the red wire you wre on about.

 

Good point - I didnt realise there was another. Autodata wasnt really helpful!

I realised that the wire into the ECU, was touching the body and blowing fuse 31 (iirc) which was for the EML.

I re-routed it and now the fuel pump runs all the time (with the ignition off)!!!

Arrgh!

 

More wires touching the body?

 

I hope not! I hate having a car that other people have been 'repairing' it makes diagnostics VERY difficult! :-(

 

The charging system is controlled via the ECU (Smart charge) when you disconnect the 3 pin plug it reverts to a conventional system.

By what you say you possibly have two separate issues.

The wiring to the said 3 pin plug can break and cause the warning light issue.

Martin

 

Yep - thats why I said I had cecked all the wiring to the plug - right back into the main harness...

I think its the ECU having a crisis tbh!

 

Ok, so got it on the diagnostics and sure enough, apart from some random airbag faults and EGR fault - there was the obligatory charge signal to ECU fault (or something to that effect!)

I am going to get another working alt tomorrow, just to put my mind at rest and if that doesnt work, will probably go down the ECU route (I will also check the second fuse box too)