If the car is left for 24 hours+, it will not start on first crank.  It's been getting progessiely worse, but to date will eventually  start after three or four attempts.

After some days of observation i noticed that

1. if the ESP / Tranction control light remained on after a second or two in ignition position, the car would not start.

2. If I waited and it went out, it would start straight away.

The garage found one code 01314  suggesting intermittent ecu comms.

I've now had a look at fuses & relays, but I can't find a definitive doc showing my particlar relay locations / idents.  NB the two under-bonnet 100 relays R1 and R2 are made by Hella and rated at 50A. Can anyone help?  It's engine code CDA.

I did originallly suspect fuel pump / fuel pump relay but now I'm not so sure.

Edited 26 April, 20233 yr by JohnBS

Update.

I ended up downloading the schematics from the Skoda database: 2700 pages of pdf.

- I've wiggled all the fuses, both boxes, and cross-swapped all the relays with identical type no's.

- the battery voltage was slighly low at 12.2(5) volts, so it was given an overnight charge with a CTEK 5A charger. The battery did not make it to the last holding charge state.

- after a short time & ignition load the battery voltage dropped back to 12.3 V which is not right for a healthy charged 12V battery, 

However, the car has not had a problem starting since these interventions, and the stability control icon goes out @ ignition position.

I've now fitted a voltmeter module in the cabin, and also swapped out the battery for the one it replaced a couple of years ago.  I'll report back if the problem recurs.

 

Did you ever find what caused your problem as I have the same errors and symtoms ! Roy. 

Roy: it's been OK so far, and i suspect the relay swap may have been responsible.  The trouble is, merely going in and disturbing things could have caused the issue to go away. 

My hunch would be try swapping the two relays marked 646 (under the steering wheel). There's still something odd about battery voltages: I'm about to conduct a further experiment with a variable power supply.

John

 

Edited 22 May, 20233 yr by JohnBS
Typo

OK, so here's the results of today's experiments.

Starting with the currnetly installed battery, (which is one which was removed a couple of years ago and has been used as an emergency spare.) 

It has sat unused in the car for a few days.

• V as found, no load 12.55V 
• V with ignition & radio on: 12.2 dropping to 12.15V (measued on battery terminals)
• Current taken by ignition + radio: appprox 7.5A

Remove battery and replace with the one removed at the end of April (a newer example of the same blue Varta ).

This battery was charged about a week ago, then left standing.

• V as found 12.8V
• Current taken by car in fully passive off-state, alarm disconnected, 25mA mean, wth  circa 1 second pulses. 

Ignition on for a few seconds, then off again

• V battery now 12.64V
• With ignition on (and fan running) 12.2V

There is significant current drain (c 2A) lasting for about a minute after switching ignition off .

So, the terminal voltage of both batteries falls from around 12.6V to 12.2V with a load in the 7 to 8A range. 

I have found a paper which models this behavior, but it was for a 96 AH AGM battery.

Accurate circuit model for predicting the performance of lead-aci.pdf

Edited 23 May, 20233 yr by JohnBS
Wrong figure

I have a 2011 Ocatvia 1.8TSI L&K and I have the exact same problem with the car! When I turn the ignition ON after 24h+ when the weather is under 10c I can hear a "ding" and a spanner symbol is flashing on the top right of the screen. If I see this then I know the car won't start. If I leave the ignition on and I wait 10-20 seconds until my dashcam boots up and starts then I can turn OFF the ignition, turn ON again and most likely the car will start without any problem! My first thought was the battery but I replaced it with a brand new one, but the problem still persist. But what is more interesting, if I don't try to turn on the ignition after I opened the car, and I connect my NOCO Boost GBX45 jump starter to the battery terminals, the car always starts immediately without any issue! If the weather is good and the temperature is over 15c this problem is never happens and I never hear the "ding" sound and the spanner is not flashing on the screen and the car always starts to the first try! I hope someone can help us to find the root of this problem because it is very annoying!

 

 

Hello,

 

@JohnBS  

May I ask where you downloaded that 2700 page PDF from?

@JohnBS ?

I would expect the answer is erWin Skoda, 1 hour access costs 7 Euro plus tax, last time I used it.

Circuits pdfs are under individual vehicle info tab, repair info option.

Download button appears when money paid.

Yes, erWin Skoda.  Massive file with all the engine, saloon/estate RH & LH drive options so it takes some time to find the appropriate data, and then it's a mico-circuit, not the bigger picuture.

On 10/06/2023 at 15:40, HyperPM said:

when the weather is under 10c I can hear a "ding" and a spanner symbol is flashing on the top right of the screen.

This is the warning that there is a battery problem. It can also come on if you are parked and using the battery - in my case listening the radio for some hours. Normally a sign of an old failing battery that cannot hold its charge overnight due to high self discharge.

I'm not entirely convinced that it's a battery problem: at lower temps the battery voltage is actually higher. If the issue is actually related to, say, the fuel pump  then it might make sense in that this electro-mechanical device is "stiffer" when cold?  The appearance of unrelated warning icons confuses the issue.

Don't confuse no load battery voltage with the on load current capability. If in doubt then get a free battery test from Halfrauds or similar where they use a high current checker.

 

You will get unrelated warnings on the dash if the battery voltage is too low while cranking. It is caused by the voltage being too low for the electronics.

See post of 22nD May

 

As this problem started directly after a timing belt change( Also water pump) I have always suspected water to electrics damage but might not be a coincidence  ?  Why so complicated ! I'm going to change the battery but no fingers crossed ! Roy. 

I have a 2011 1.8 TSI Scout, and my layout under thed dash is the same as your photo, but I (and my garage) cannot find the fuel pump relay - did you find it or know where it is on our models please?

This is what I have for the Octavia relays under the dash: D2.2 is listed as fuel pump. But on my car only two of thse relay are present: D5.1 and D2.1, neither labeled as fuel pump! ( 2.1 Horn relay)

Edited 23 September, 20241 yr by JohnBS
More data

Here's the other bank: both layouts are for RHD Octavia II

 

Thank you, mine looks like the second, but like your previous photo mine is missing number 4 and the 646 above it is the horn...why is it so hard to locate!

@ggpowell2,  if you supply reg number or VIN, I can locate the most relevant info for the car. There are different schematic sets for pre- and post May 2011.

3 minutes ago, Breezy_Pete said:

@ggpowell2,  if you supply reg number or VIN, I can locate the most relevant info for the car. There are different schematic sets for pre- and post May 2011.

That would be so helpful, thank you, TMBKK21Z6B2172679

Yes, ditto: there are so many versions of the schematics, it gets ovewhelming.   My reg is FT11 JZP

John

Just about to do a spin class fellas, will get to it later this evening.

 

Thank you, enjoy spin 😊

Having trawled through the  schematics I have (relating to the CDAA engine code) - it looks like there may be no relay: rather, a fuel pump control unit

 

On top of the fuel pump under the rear seats?