Discovery 4 electrics turn off while driving

Back in the eons of time I was advised by a very good mechanic that the biggest mistake made by vehicle manufacturers was to not fit an earth connection between the battery negative terminal and the engine block, From personal experience this connection will cure many issues experienced with ignition electrics and improve engine performance. Any voltage drop will affect any engine electrical system performance.

Applying this simple process may resolve your unreliability problem.

So can finally provide an update & resolution to the electrical issue.

After several months of good behaviour it started again last week. Got it to Autocode & they were able to observe it faulting while plugged in to diagnostics.

Ended up being a wiring short on the medium speed Can bus. Repaired & seems to be running fine.

Not a cheap fix due to needing several hours manually testing to find location of fault plus time to remove & replace panels etc, but more than happy to recommend Mark at Autocode for doing a good job.

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Originally Posted by Steve86

So can finally provide an update & resolution to the electrical issue.

After several months of good behaviour it started again last week. Got it to Autocode & they were able to observe it faulting while plugged in to diagnostics.

Ended up being a wiring short on the medium speed Can bus. Repaired & seems to be running fine.

Not a cheap fix due to needing several hours manually testing to find location of fault plus time to remove & replace panels etc, but more than happy to recommend Mark at Autocode for doing a good job.

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It's always good when they don't start throwing parts at it. As my mate says, mechanical issues, 1hr to find 10 hr to fix. Electrical issues 10hrs to find, 10 minutes to fix

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Originally Posted by Steve86

Ended up being a wiring short on the medium speed Can bus.

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Can you advise where the short actually was?

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Originally Posted by josh.huber

It's always good when they don't start throwing parts at it. As my mate says, mechanical issues, 1hr to find 10 hr to fix. Electrical issues 10hrs to find, 10 minutes to fix

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Yep - was charged exactly 10 hrs of labour.

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Originally Posted by DieselLSE

Can you advise where the short actually was?

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Was told it was wiring running under the front passenger seat - I assumed power seats are on medium speed can bus?

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Originally Posted by Steve86

Was told it was wiring running under the front passenger seat...

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Interesting. I have a theory that it is more likely an overlooked but, in hindsight, a heavy trafficked area where wiring can be compromised. By that I mean an area where the wiring may be being moved or rubbed or exposed to excessive heat etc. Under electric seats is not a benign area, particularly if the space is used to house tools etc., or if rubbish is left to accumulate. Or, of course, it could just be bad luck or a bit of dodgy wiring!

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Originally Posted by DieselLSE

Interesting. I have a theory that it is more likely an overlooked but, in hindsight, a heavy trafficked area where wiring can be compromised. By that I mean an area where the wiring may be being moved or rubbed or exposed to excessive heat etc. Under electric seats is not a benign area, particularly if the space is used to house tools etc., or if rubbish is left to accumulate. Or, of course, it could just be bad luck or a bit of dodgy wiring!

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Mouldy pizza trays and half empty travellers will cause all sorts of mayhem.

DL