Thread: D4 complete shutdown while driving

Hi simoncs, if you have a digital multi meter, measure the voltage at both batteries.

From what you have posted, while it could be a loose connection, that sounds like the classic sign of an alternator failure.

If so you will need to disconnect the neg from both batteries to protect them from being flattened and damaged by the alternator.

Originally Posted by drivesafe

From what you have posted, while it could be a loose connection, that sounds like the classic sign of an alternator failure.

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thanks - i measured the voltage. it seemed fine - about 12.25 with engine off, and then 14.5 with engine on - so i guess the alternator is working.
However, as you suggested, there was a wire that had pulled out of it's connector, for the UHF, so maybe this could have been it.
Hopefully when it goes for the service they might be able to see from the error messages.
thanks for your help.

so car went for service and they didn't find any faults. i had already recrimped the loose wires so they agreed it coukd have been that. i had skso reported that the csr felt sluggush pulling away and sometimes had a jolt. This they reported was the infamous brake switch which was faulty so they replaced it.
had no issues driving home, or yesterday, but today the issue reappeared. complete shut down whilst driving. not cool when i have my kids in the car! it hsppened acfewctimes as i nursed the car home. the jolting also got much worse. sometimes no power at all but car remained running then liads of warning lights. the car seemed tk be shutting down when ever i braked or slowed down. not everytime, but that was the only pattern i could see. Also when i was in the carpark whilst reversing. checked all the wiring again and all looks fine, so will take it back to the dealer snd hope there are some faults they can trace.

Sheesh mate bloody no good at all as you say especially with the kids in the car!! Fingers crossed they can find it!!

Hi again Simon and is this a D4?

If so, try disconnecting the dual battery system and see if the problem gets worse.

I suspect it may still have something to do with the alternator or the BMS.

The reason for this suspicion is that you say it occurs when braking or slowing down.

By slowing down do you mean you have your foot on the brake peddle or are you just backing off on the accelerator?

Originally Posted by drivesafe

Hi again Simon and is this a D4?

If so, try disconnecting the dual battery system and see if the problem gets worse.



By slowing down do you mean you have your foot on the brake peddle or are you just backing off on the accelerator?

yes foot on the brake pedal and it is a D4 2012.

Hi Simon, there is something on the UK D3 site about problems where faulty brake peddle switches have caused some strange problems.

I have not searched for it but will do so when I get a chance.

sorry to let the team down guys, but a tow truck is on it's way tried nursing the car back to the dealer but have stalled about 20 times, so for safety have pulled into a side road and called lr assist. will be a shame to see it on a flat bed.