Strange problems and codes

[Pondrew]

Ever since we have had the latest E89 (the 2016 waterlogged boot blue one), which is now three months, there have been a few 'issues' which have been random and very intermittent.

After a few days of acquiring it a 'low battery' warning came up. OK, so it may have been stood for a while, so charged the battery with my cTek.
All good. Then after a few days my lovely wife said the car had 'no power' on her way to work. I questioned her, but put it down to the previous E89 having been chipped so was a lot more powerful than the bog standard 20i we have now.

Then a few weeks ago it flashed up an 'engine fault, drive slowly, take it to the nearest rip off BMW dealer' kind of thing. Got the codes read by the AA, which said it was a knock sensor, on 2 cylinders 'short circuit'. There was also a code for turbo boost pressure but that seems interlinked to the knock sensor.
That fault, once cleared, has not come back. I put it down to moisture in a connector which I can't find.

Today we drove 40 miles to visit our forum friends and about a mile away from our destination, the throttle just stopped working for about 10 seconds. There was nothing when I pressed the loud pedal. The car was still running but just coasting. Ten seconds later all burst back into life. This is what my wife was trying to explain happened three months ago when we first got the car!
I nursed it back home and it was fine all the way.
Read the codes once home. Nothing relating to the throttle issue but it came up with "31E9 electric fan disconnection". It also had a really odd code for all four main speakers being open circuit.

The electric fan worked (to cool the radiator) and all speakers work as normal.

One thing I noticed was if I turned on the A/C, the fan would not run at all. The A/C then tripped on it's HP switch and the engine was getting really hot. I had to turn the car off, turn the A/C off and then the fan would run on the radiator thermostat and cool the engine.

So I switched the car off, left it a few minutes and tried again. No codes (at all) and the fan was working properly with the A/C and on the rad thermostat. I left it like this for a good few minutes and all was as normal. No codes re-appeared.

Scratching my head I switched the car off, left it about 5 minutes and checked the voltage of the battery. Bearing in mind the car had been driven 80 miles today (2 roof movements both with the engine running) and been ticking over on the drive for a good half an hour, the voltage was 12.6v.

So I have ordered a new battery, as I have a feeling (or hope) the battery is knackered and causing havoc with car.
The throttle issue is really odd, but could it be voltage related?

Sorry for the long post!

[mr.tourette]

A knackered battery can throw up literarily any fault thats electronic related so yeah you should assume it could throw up a fault with the throttle as it has a few sensors.. not saying it is battery related but it could be

[matsmith749]

Having seen a ton of weirdness from poor batteries, my gut feeling is that these symptoms are not typical indicators of a bad battery.

What are you scanning for codes with? Will it show code history for intermittent faults that are not present at the time you scan?

I would expect to see something recorded that could shed more light.

[Pondrew]

Having seen a ton of weirdness from poor batteries, my gut feeling is that these symptoms are not typical indicators of a bad battery.

What are you scanning for codes with? Will it show code history for intermittent faults that are not present at the time you scan?

I would expect to see something recorded that could shed more light.

I have a Creator 410. I was under the impression that codes would be stored until manually cleared.

I checked the live data on everything with the engine running. Nothing at all seemed odd.

The car only has 25k miles on it; decent service history. BUT it has a cheap looking battery (NAPA) and the faults are so random.

The throttle fault was weird. It was like it 'forgot' the throttle was connected then remembered after a few seconds. This has now happened twice in three months and 1,000 miles.

[matsmith749]

I would suspect that NAPA battery... its not the standard fitment. Worth changing just to rule it out I guess (cheap), then take it from there.

My gut tells me something is broken / bad connections somewhere which will need tracking down.

[MikeyH]

I hope I’m not stating the obvious but would the water in the boot have caused these problems as that’s where the battery lives?

[Pondrew]

I hope I’m not stating the obvious but would the water in the boot have caused these problems as that’s where the battery lives?

Who knows, Mikey?
Unlikely as the battery is about 8 inches tall and there was a lot of water in there, but not quite that much!

[Pondrew]

My gut tells me something is broken / bad connections somewhere which will need tracking down.

Yes, that is my fear. The knock sensor issue was a connection/ connector issue I think.
Also (which is worrying me) one of the front hoses in the engine bay has foam insulation around it and that has been eaten by mice at some point (you can see the nibble marks). If they have been at that, who knows what else they have nibbled?

But if there was damage to insulation/ cables I would expect the problems to be a lot more common. The time scales are long way apart. I have visually checked everything I can see and all looks perfectly OK.

I hate cars!

[Pondrew]

The wife took the car out today with no issues. She did about 40 miles.

When she got home I thought I would read the codes just to see....

The strange speaker codes were back, even though they all work correctly.
And a new one! AUC sensor fault.

I checked the battery voltage and it is down to 12.4v from yesterday, after a 20 x 2 mile drive.
New Varta battery should arrive tomorrow so fingers crossed.