Are you referring to the ones circled in the attached photo? I don't have the skills needed to test or replace these myself, but a few people at my work are able to do this kind of thing. Cheers


Yes those are the ones. l am not sure what errors come up when they fail, but the symptoms are engine stops and you get no fuel pump, no temperature gauge, no EML light and no glow plug light
 
There are also cases of component failures(especially resistors or chips) which will not let the ECU communicate with a scantool.
Too right!
My first ECU, the one that got dropped, and had been chipped (Grrrr!) promptly fell off the communication horizon, so i had to replace it with an ornery one. Even a clever lady engineer with a microscope couldn't find a break on/ in it.
 
Yes those are the ones. l am not sure what errors come up when they fail, but the symptoms are engine stops and you get no fuel pump, no temperature gauge, no EML light and no glow plug light
I received my broken ECU back today, but sadly this is not how it behaves when I give it a try. Everything works normally, apart from it will crank and crank, but just won't take (I'm sure fuel is not being injected).

Cheers for all of the pointers though. Any other ideas, or is it time to move on and buy one off eBay?
 
Try a call to "Mastaz TD5" (google it)

He's local to me and really seems to know his stuff, he may be able to repair it for you.
 
I received my broken ECU back today, but sadly this is not how it behaves when I give it a try. Everything works normally, apart from it will crank and crank, but just won't take (I'm sure fuel is not being injected).

Cheers for all of the pointers though. Any other ideas, or is it time to move on and buy one off eBay?
measure voltage while cranking, if it dropd below 10.5V it wil not start and if you have nanocom or similar make output tests for the injectors to hear them clicking
 
measure voltage while cranking, if it dropd below 10.5V it wil not start and if you have nanocom or similar make output tests for the injectors to hear them clicking
The truck runs perfectly with my other ECU, so I think I'll just buy a working one from eBay as a spare
 
The truck runs perfectly with my other ECU, so I think I'll just buy a working one from eBay as a spare

They are around £700 on Ebay, Discovery ones are cheaper but they don't work properly in the Defender (which is why they are cheaper....nobody wants them)

l would try getting yours repaired first, the guy l recommended above charged me £80 to do mine
 
They are around £700 on Ebay, Discovery ones are cheaper but they don't work properly in the Defender (which is why they are cheaper....nobody wants them)

l would try getting yours repaired first, the guy l recommended above charged me £80 to do mine

Thanks, I'll give him a buzz
 
I've just had my dodgy ECU checked with a Nanocom, and the results are somewhat unexpected...

When it first failed, it was showing Topside Switch Failure and Injectors 1-5 Open Circuit, but this time it wasn't showing any errors at all (except ABS and Aircon, but they were expected).

Communication with the ECU was definitely fine. Any ideas what no error codes could mean?

Cheers
 
Small update here, in case it's helpful for anyone...

I'm told that a faulty ECU that is not showing any error codes, but that communicates ok with a Nanocom, could mean that the main processor is playing up and needs replacing.

A friendly electronics engineer from work is looking at this for me, so it'll be interesting to see what the outcome is. I know it probably makes more sense just to buy a used one of eBay, but I enjoy the challenge!
 
I'm told that a faulty ECU that is not showing any error codes, but that communicates ok with a Nanocom, could mean that the main processor is playing up and needs replacing.
It depends, can you read live inputs while cranking with that ECU? cos if the processor is gone it will not show any data
 
Have you checked the surface mount resistor banks around the microprocessor IC?

lf faulty they can be bridged with a regular resistor but it takes a bit of skill with the soldering iron to do it.
 
It depends, can you read live inputs while cranking with that ECU? cos if the processor is gone it will not show any data
I've not tried this specifically yet.

Have you checked the surface mount resistor banks around the microprocessor IC?

lf faulty they can be bridged with a regular resistor but it takes a bit of skill with the soldering iron to do it.

These are on the list for my colleague to check, along with some other components, before we have a go at replacing the the processor as a last resort. Hopefully it won't come to that!
 

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