[fortythirtyfive]

So I’ve been having my ABS flash up as failed recently and it vanishes within seconds, usually the radio goes quiet and sometimes the kombi goes dark but it sorts itself out within half a second.

This has happened maybe 3 or 4 times in the last 2-3 months, however after doing an airport drop off this morning it flashed up again, this time telling me of a drivetrain and transmission fault, along with no power steering and no internal electrics. It kept failing persistently over and over again, after the 5th or 6th time it stopped for around 60s before cutting the entire car power. The gearbox started whining as I came to a stop although I believe this may have been my ghost immobiliser locking the gearbox.

I’m now kind of afraid to drive the car as it’s super random as to when it does it, but I lost power steering on a sharp bend and wouldn’t like to experience it again.

There’s zero faults logged, nothing on the dash so it would seem to me like an electrical fault. Could I be right in thinking a weak battery might pose this issue? I did have a battery discharge warning yesterday as I had been working on the car with the ignition on. The only thing in common to trigger the issue is I have always been coasting

[n55david]

Originally Posted by fortythirtyfive

So I’ve been having my ABS flash up as failed recently and it vanishes within seconds, usually the radio goes quiet and sometimes the kombi goes dark but it sorts itself out within half a second.

This has happened maybe 3 or 4 times in the last 2-3 months, however after doing an airport drop off this morning it flashed up again, this time telling me of a drivetrain and transmission fault, along with no power steering and no internal electrics. It kept failing persistently over and over again, after the 5th or 6th time it stopped for around 60s before cutting the entire car power. The gearbox started whining as I came to a stop although I believe this may have been my ghost immobiliser locking the gearbox.

I’m now kind of afraid to drive the car as it’s super random as to when it does it, but I lost power steering on a sharp bend and wouldn’t like to experience it again.

There’s zero faults logged, nothing on the dash so it would seem to me like an electrical fault. Could I be right in thinking a weak battery might pose this issue? I did have a battery discharge warning yesterday as I had been working on the car with the ignition on. The only thing in common to trigger the issue is I have always been coasting

a low battery can cause all sorts of issues. check the life of your battery and start there. I wouldn't think it would cause the problems you're experiencing but who knows.

[fortythirtyfive]

Originally Posted by Phantom10R

a low battery can cause all sorts of issues. check the life of your battery and start there. I wouldn't think it would cause the problems you're experiencing but who knows.

So I gave it 2.5 hours on a car battery charger (it's an industrial huge thing not one of those small charge pack ones). It read the battery as "good" and when I metered it I was getting around 13.4v

Haven't had an issue since, however I cannot read any codes until my new cable arrives tomorrow. Slightly concerned though as my O2 sensors have now died, I run a catless dp and doing 10k miles each year means every 12-14 months I have to buy new sensors due to them burning out.. so it's either a really weird coincidence or something isn't happy.

[fortythirtyfive]

Looks like it was an under voltage issue, looks like the battery condition majorly affected it.

I'm going to look for a new and bigger battery, hopefully that'll help with any drain issues.

[thejeremyman9]

Originally Posted by fortythirtyfive

Looks like it was an under voltage issue, looks like the battery condition majorly affected it.

I'm going to look for a new and bigger battery, hopefully that'll help with any drain issues.

Make sure you do proper coding/register for new battery once you get one.

[fortythirtyfive]

Is there a health check I can do other than metering my battery?

I have used two different meters now on the battery and whilst running I was getting readings of 12-13v's.. when I check the codes via the MHD app however it's reporting mid 14's so I'm now skeptical whether the battery needs replacing lol

[thejeremyman9]

Originally Posted by fortythirtyfive

Is there a health check I can do other than metering my battery?

I have used two different meters now on the battery and whilst running I was getting readings of 12-13v's.. when I check the codes via the MHD app however it's reporting mid 14's so I'm now skeptical whether the battery needs replacing lol

Aside from basic voltage checks after sitting overnight, etc, you need to get a proper load test on the battery.

[5w20]

Originally Posted by fortythirtyfive

So I’ve been having my ABS flash up as failed recently and it vanishes within seconds, usually the radio goes quiet and sometimes the kombi goes dark but it sorts itself out within half a second.

This has happened maybe 3 or 4 times in the last 2-3 months, however after doing an airport drop off this morning it flashed up again, this time telling me of a drivetrain and transmission fault, along with no power steering and no internal electrics. It kept failing persistently over and over again, after the 5th or 6th time it stopped for around 60s before cutting the entire car power. The gearbox started whining as I came to a stop although I believe this may have been my ghost immobiliser locking the gearbox.

I’m now kind of afraid to drive the car as it’s super random as to when it does it, but I lost power steering on a sharp bend and wouldn’t like to experience it again.

There’s zero faults logged, nothing on the dash so it would seem to me like an electrical fault. Could I be right in thinking a weak battery might pose this issue? I did have a battery discharge warning yesterday as I had been working on the car with the ignition on. The only thing in common to trigger the issue is I have always been coasting

Voltage isn't the only thing you should be concerned with on a battery. It seems like your battery can no longer take a small load and it is stressing it down low enough to cause an electrical issue.

I would definitely replace the battery.

[fortythirtyfive]

Originally Posted by thejeremyman9

Aside from basic voltage checks after sitting overnight, etc, you need to get a proper load test on the battery.

Remembered I had bimmerlink on my phone from a few years back, it read the battery as 62% charged after 5+ hours on a battery charger. I went for a short drive and it jumped up to 74% but I'm going to monitor it.

Originally Posted by 5w20

Voltage isn't the only thing you should be concerned with on a battery. It seems like your battery can no longer take a small load and it is stressing it down low enough to cause an electrical issue.

I would definitely replace the battery.

Yeah I'm going to just pull the trigger, need to do a bit of shopping tonight I think!

[thejeremyman9]

Originally Posted by fortythirtyfive

Remembered I had bimmerlink on my phone from a few years back, it read the battery as 62% charged after 5+ hours on a battery charger. I went for a short drive and it jumped up to 74% but I'm going to monitor it.



Yeah I'm going to just pull the trigger, need to do a bit of shopping tonight I think!

Is your battery charger made for AGM batteries? That can affect the % they show I believe.

The car typically wont charge to 100% FYI. As noted above though its about more than voltage/%. It needs to be able to handle a load.

[fortythirtyfive]

Originally Posted by thejeremyman9

Is your battery charger made for AGM batteries? That can affect the % they show I believe.

The car typically wont charge to 100% FYI. As noted above though its about more than voltage/%. It needs to be able to handle a load.

The charger is yeah, although the percentage read out was via bimmerlink.

I managed to find a huge discount for a Exide 105ah replacement, it came down to £120 so I snapped it up