VW Golf mysterious flat battery
The Mrs’s golf had a mysterious flat battery over the weekend. No lights, radios etc were left on. After a jump start it now starts fine, but since the flat battery the ABS and power steering warning lights are on, and the steering feels a little odd. Anyone know what would cause all this?
Something similar happened 18months ago where the ABS warning light came on after a similarly mysterious flat battery that the garage couldn’t work out what was up. Faulty computer?Posted 3 years agofinishthatSubscriber
VAG cars have fusible links in connections made in the battery cover lid. They are 40/50 + amp links – These flat links develop cracks and lead to problems with power steering and ABS etc.Posted 3 years ago
To check the links rub them with a small screwdriver , the hairline crack will open up if they exist – spares from any VAG dealer – sometimes there is a spare bolted in place – but it may be the wrong rating.CougarSubscriber
One of my previous cars had a constant fault like this that my mechanic couldn’t find the cause of, even after a new battery was fitted.
Anecdotally, I’ve had one of those. Half the time it’d start perfectly, otherwise you’d get “click” and it was dead as a doornail.
Long story short, weeks of going through several mechanics and auto-electricians failed to diagnose a faulty rectifier on the alternator. Ended up taking it direct to Lucas who found and fixed it in under five minutes.
Dunno as that helps the OP though; sounds like a fault on one of those subsystems mentioned is draining the battery.Posted 3 years agounfitgeezerMember
but since the flat battery the ABS and power steering warning lights are on, and the steering feels a little odd
from memory when had a touran turn steering wheel full lock both ways not sure if car was running or off but try both…prob was running.
this should sort it out !Posted 3 years agomaxtorqueMember
Have you had a full diagnostic scan done?
Modern cars use “smart” charging, and flat batteries can be caused by a huge number of things, from faulty modules not going to sleep as they should, to the SOC sensor failing and a million other things. One thing is for sure, you (probably) won’t fix it by guessing!Posted 3 years agoz1ppyMember
Again, how old is the battery, mine died overnight (6 year old car), no warnings at all but was sorted with a new battery. As for the warning lights, I checked all my fuses for another fault (removed & checked), the steering & electronic drive assist lights suddenly added to my woes (freaked me out). I took it for a drive & they cleared themselves within a mile or two.. Have you tried driving it far?Posted 3 years ago
As above, had mine checked for other faults using the ecu reader, done by my mechanic m8 ( far from an electronics specialist)muzzMember
Sounds like the fan belt, alternator belt or aux drive belt (however you call it) may have snapped meaning the alternator is not charging the battery and not powering the power steering properly. It is also likely the water pump is not working and your car may be in danger of overheating.
Look in the engine bay and see if it is still on the pulleys.Posted 3 years ago
You’d know if the alternator wasn’t supplying charge – red battery symbol.
The airbag and ABS etc lights are nothign to worry about – if you have a battery go flat, they come on, they should go off again after a bit. If you are near South Wales (or possibly London) I can read the fault codes for you and give you a few pointers.Posted 3 years agomaxtorqueMember
A simple check you can do, with a normal multimeter in current measurement mode is to measure the “sleep” current of the car. When you key off (ie turn off the ignition) some modules immediately go to sleep (like the engine controller for example) but others (infotainment, Nav, telematics etc) stay alive and only go to sleep after the car is locked (and generally after a delay post locking). You can measure the current draw from the battery say 15min after locking the car (you might need to “fake” a bonnet shut signal btw) to see if some modules are not shutting down and flatening the battery.Posted 3 years agocoffeekingMember
The airbag and ABS etc lights are nothign to worry about – if you have a battery go flat, they come on, they should go off again after a bit. If you are near South Wales (or possibly London) I can read the fault codes for you and give you a few pointers.
Not on any of my cars, never had them come on and have had many duff batteries!Posted 3 years ago
Molgrips: How would you clear the faults? Someone recommended this…
would that sort of thing be any good / worth getting? Based in cardiff btwPosted 3 years agounsponsoredMember
GF has a 06 golf. We had a similar issue with returning to a car with a flat battery. Turns out there is an issue with radios spontaneously switch on. Only noticed it when we had returned back to the car and could hear the music. VW replaced the radio as it was a well documented fault.Posted 3 years ago
At the moment the battery is not the problem as its been fine now since we jump started it, which probably rules out some of the causes mentioned. But obviously something made it go flat its just odd that it hasn’t happened since the weekend, unless its to do with dodgy electrics. The power steering and ABS warning lights are still on and the steering does feel occasionally heavier than usual.
very grateful for your offer molgrips, and will take you up on that, ill send you an emailPosted 3 years ago
It would be worth checking as it’s quite common for the alternator load management wire to break which stops the light coming on at all. The battery can have just enough juice to run the car but load management starts shutting down high draw systems (electric PAS on yours?) as it can’t regulate what’s going on.Posted 3 years agomcmoonterMember
It would be worth checking as it’s quite common for the alternator load management wire to break which stops the light coming on at all
I think this happened on our old Passat. The battery would appear to discharge over night, but in effect the alternator was barely charging. The nail in the coffin was a cold winter day with the fan, lights and blower on. The engine cut out and wouldn’t restart. Charging check confirmed nowt between the terminals.
Rather than faff about we bought another car. I need to get another alternator and see if cures the charging issue. Its a bit of a faff as the front end of the car needs to come off to remove a single alternator bolt. Who designs stuff that dumb?Posted 3 years ago
Just been down to check, battery light on when ignition on, goes off when car starts. Also checked all the fuses, the fuse box in the engine were all fine, the fuse box inside the car had one broken fuse. This fuse wasn’t listed in the car manual but should not be connected to the problem as these are fuses for interior stuff like seat heaters, blowers etc (i think).Posted 3 years ago
In that case I’d start by pulling the fuse for the radio, give the battery a good few hours charge and check the voltages – off, idling and with a load on the battery. The lights on the dash will most likely need resetting with a diagnostic tool as they’ll have been generated by the low voltage of the flat battery.Posted 3 years ago
Thanks for the input dai… Would i need to do that despite the car starting fine since it was jump started on sunday? Prob done over 100 miles since then.
Ill see if i can something to read the voltages. Any idea what they should be or will this be in the car manual or should i google it?Posted 3 years ago
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