Fault code 5DF4 (low voltage) any ideas?

J

JPmagic

Member
Hi Guys, new to the forum as I'm just about (or was) purchase a 65 reg Z4 coupe. its a private sale and i went to view it yesterday. lovely car and the test drive was great but when returning after a 10min drive the engine light came on (orange engine symbol) and it wouldn't go off.

Obviously i didnt buy the car due to this but the current owner said its never happened before and will get it plugged in at a local garage and he will get back to me. Today they have said the fault code 5DF4 which means low voltage has flashed up but currently isn't a present fault so it reset ok. The current owner is going to drive it for a few days and let me know if it returns.

What do you think guys? hes tested the battery and its 11v static and 14v running so thats all good. just the description seems a bit brief to me "low voltage" could be any sensor playing up in my eyes. i just don't want to run the risk buying it and i spends loads at BMW on labour trying to trace the fault or is this a common fault and an easy fix?

any you guys heard this code before?

Thanks in advance :thumbsup:
 
Standing battery voltage should be around 12.6v, 11v suggests a dead battery. Voltage alone won't tell you if a battery is 100% you need to do a load test. I would suggest it needs a new battery and if it's of the AGM type there about £180.
 
Sorry i got it wrong, I've re-read his message and its 12v standing and 14.2v running. Just don't understand if it is the battery why didn't the light come on as soon as we started the car (also the car had been out that morning too) i was testing all the functions like heated seats and air con to see everything was working as it should so there would of been high demand from the battery i guess. Just dont know if i should take it as it is and knock off some cash so i can get it into a decent specialist but doing that i could be losing major money if its a major fault.

I take its not a major fault though as ive read the engine light would be flashing? Also has is there a separate light for the DSC or due to it being a 10yr old car do all faults come up through the engine symbol?
 
Alternator sounds fine but battery needs replacing, even at 12V it's underperforming. If it's used as a daily I'd be investigating for a drain, if not then it could simply be that it has been sat unused for too long. When the car is running the alternator will pick up the slack, if you've maxed everything out then that's the point at which it may have struggled to cope and the reason for the light.

Standard battery can be had for £60 online, I presume you mean a 56 plate coupe.
 
yeah i mean 56 plate coupe, yeah it does sound its pointing to just a faulty battery, just messaged the owner and he said its the original one and plus its a weekend car (its only don't 3k miles since December) so makes sense.

Think I'm going to go for it as not letting that pass my fingers just because of a battery

Thanks for your advice guys! and I'm sure i will continue to use this great forum :thumbsup:
 
Will the owner not replace the battery himself prior to sale? That's what I'd be looking for to ensure all is well :thumbsup:
Rob
 
its currently at the garage and the battery is being charged overnight (quick fix i guess) I've already knocked him down a fair bit but i will say to him that its 10yrs old and that its obviously starting to fail so at least knock off another 100 so i can get one myself
 
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