I already had a lot of help to fix broken gear selector - thanks!

I also found that the passenger side front suspension spring has broken - so I'm off to the garage for that!

However, electrical issues ongoing. Here's the story:

skoda octavia mk3 2013 tdi estate

Car sat for 8 months.

AGM battery flat and won't recharge

New AGM battery

Not recoded as yet.

Battery at 11 volts.

On overnight charge with smart charger AGM, rises to 12 volts.

clicking sound (starter solenoid?) when battery is attached, it persists when engine is running

engine warning light

glow-plug warning light

Airbag warning light

ABS warning light

alternator putting out only 12 volts - i got a multimetre onto the altn but its impossible to get a good view of the connections at the back of altn. in situ.

Serpentine belt is running smoothly.

At battery connector, when engine running, 12 volts only. Rises a bit when engine reved.

Coolant level low, topped up and after short run, coolant level dropped 20%.

I took off the under engine cover. No sign of any leaks.

Oil level good and stable.

Fusebox under bonnet checked. All fuses okay.

Earth connector battery to body good.

On visual inspection no obvious wires or connections loose or damaged.

Any suggestions or help ? Thanks in advance.

step 1 replace the battery if you haven't conditioned it to a min 12.2v

12v sounds low. Battery is a critical part of any car, if you can't condition it to usable then replace.

Not withstanding there is still possible other issues though like alternator but at least you are starting from known good.

Once replaced - scan and clear all errors, you can use the non pro version of ODBEleven or similar interfaces to do this.
I'm talking from recent first hand experience as I had a multitude of errors caused on a low battery car gifted to me but had been standing.

I also found some errors seemed sticky but driving this car (DSG) seemed to resolve most of them. I have found some intermittent ones but that seems quite common for any old cars and can be a case of trying to resolve them one by one.

e.g.

   B116229 - Selector lever park position lock switch implausible signal
            Intermittent
Quick google / you tube video for this indicates an upgrade bit of wiring. Its just something I've seen quite sporadically show up not all the time and must be a well known fault. It doesn't mean it needs any immediate attention and can still drive the car in the meanwhile.

Also
"coolant level dropped 20%."

This would also bother me a little, in my history you are either talking coolant loss, thermostat failure ( its stuck shut and boiling off the coolant) or HGF

( sometimes can result in a direct external leak from head - like I had with one of my non Skoda cars with a weak design elastomer gasket and was replaced with triple metal - or it might be directly mixing the oil and coolant through breakdown of the gasket material which should be obvious, after running will be signs of mayo such as on the dipstick )

Thanks vRSant. It's a new battery so I don't think the issue is the battery. Its a manual gearbox, i should have stated that. The OBDeleven non pro version allows me to recode the car to the new battery? This is via a device that I'll need to buy I think. It that right?

Ah I didn't read properly sorry, so its a good battery that if conditioning should reach over 12.5V? Lidl do cheap ones which is where I got mine from.

Ah the recoding -
Sorry you will need PRO (or be inventive in looking for an APK at own risk) to find a way to do that, maybe a VCDS member local to you might help ?

12V sounds low from your smart charger though, are you sure the new battery isn't borked?
My new one was over 12.5V and I think on charge was North of that around 13V

In my honest opinion for coding I would bite the bullet and get full proper VCDS ( no cheap copy virus china edition ) and just determine how many license you need for it.

I think OBD11 is alienating people with its insistence of yearly annual which isn't exactly low, if you can imagine needing for a few years I think it may pay for itself in hobby coding - or pro if you start helping others

Its a different platform with OBD pushing more to mobile BT users vs laptop/usb admittedly but VCDS was always the daddy.

7 minutes ago, vRSAnt said:

12V sounds low from your smart charger though, are you sure the new battery isn't borked?
My new one was over 12.5V and I think on charge was North of that around 13V

AGM Smart charger should be running above 14VDC on a discharged battery, as should the alternator - even though the new battery has not yet been adapted into the vehicles BCM.

Because you are seeing low charging voltages for both the charger and the alternator, I suspect your new battery may have a high internal resistance fault - or possibly a bad earth connection.

For the coolant loss, check the EGR valve and have the coolant tested for combustion products.