Intermittent fault thats baffling

[arrolman]

Had an ongoing intermittent fault for the past year thats really beginning to piss me off. When driving the oil warning light will come on and the van will lose power, as though the turbo switches off, happens for a second or two then goes back to normal. However, sometimes the engine cuts out and or appears too. Driving to work this morning it happened and noticed the lights dimmed then came back on full once oil light went off. I have changed the prv/scv(Genuine) full update and all learns in past 6 months. Gets serviced every 6 months on the dot. EGR deleted, inlet manifold cleaned, all sensors checked. Only fault codes I sometimes get are turbo underboost/turbo overboost, battery de-energised too soon. Codes only appear now and again, not every time. Anyone got any ideas of where to look? Its been in garage 3 times, as usual it never happens when they have it so can't replicate it or get an idea of when/how its happening. Have also checked all ECU connections etc and all good. Can run for a week not doing it then will do it 3 times in a journey the next. Does it if feet are on pedals or off, I'm stumped. MK7 2.4 140

[STEVE P]

Check your earth leads to the engine.

I had a problem with a car a few years ago intermittently loosing power and it turned out that main earth connection bolt to the engine was not tight. Once cleaned and tightened I never had the problem again, as you say it would happen 3 times in a journey and be fine again for a week.

Steve

[knobby1]

Ignition switch is a common "intermittent" fail point too.

Lord Knobrot

[arrolman]

Hi guys,

Earth leads might be a shout, will check them out. Ignition switch was changed few months back. Also had 2 new batteries

[Airthies]

Check battery terminals.

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[Frag]

I’ve just had this fault on a customers van,the PCM relay in fuse box under bonnet had corrosion in its terminals and some in the relay itself.

[arrolman]

Thanks for the pointers guys, will get into it in next few days, much appreciated

[arrolman]

Still no joy with this. Stripped earths at drivers seat and inner passenger wing and cleaned up, took all relays and fuses out engine fuse box, cleaned all contacts, no visible signs of corrosion or moisture. Anyone any other ideas?

[Airthies]

What is the code for the de-energised fault? P068..... A or B.

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[arrolman]

Hi Airthies,

Its P068A. Also had P0299 and P0234 regards turbo. All clear no problem and only return once the oil light comes on and drops power for that second or so