Skoda Fabia I - The car does not start after replacing the battery

Skoda Fabia I 2008 1.4 petrol engine.
Marelli 4HV engine driver.
After changing the battery, which lasted literally a few seconds, the car stopped ignition.
When trying to run for several seconds, it shows no signs of life.
During subsequent attempts, the yellow indicator light of the "car with the key" flashes and the car lights up for a second and then goes out.
An error appears in immo:
- 01177 Damaged driver, Unauthorized, discontinuous

In the engine driver error:
- 17978, Electronic engine control module blocked, Steel

The next day he appeared in the ECU
error:
17069 - ECM / PCM power relay control open circuit
- discontinuous

On the third day, the car behaves so that it does not crash any errors in any of the controllers. Immo sees two authorized keys. After ignition, you can hear the fuel pump, turns the starter, but will not even talk for a moment. After approximately 5 seconds of turning, the red oil lamp and the dash signal flash.
What is going on? Where to look because your hands fall down.

Any added alarm / security is not sitting by accident?

milejow wrote:

Any added alarm / security is not sitting by accident?

There is an alarm, but it works correctly and is disarmed, i.e. in service mode. What makes me more concerned is that there are different symptoms and different types of car behavior. Maybe some strange coincidence happened. Maybe someone knows which relay corresponds to the controller power supply?

osliczka wrote:

There is an alarm, but it works correctly and is disarmed, i.e. in service mode.

While searching for a fault, connect the alarm pins responsible for cutting off with a piece of wire.
You will be 100% sure that it is not a broken alarm that stops the vehicle.

I always thought it couldn't be done, but there are those who can ... Didn't the battery connect upside down?

It is not raining immo since replacing the battery, unless it was charging the battery connected to the car with a type rectifier and the pins detained something. I don't know about volatile memory because I have the same kind of myself so I don't remember.

sk700 wrote:

I thought about it too. There is also an option to disconnect the battery when the ignition is on when the processor was writing something to this memory.

Yes, theoretically, if the ignition was on, even after turning it off with the battery disconnected, you should wait for the electronics to "sleep", i.e. usually a dozen to several dozen seconds. I used to try very hard in my Grande Punto ... the result was a checksum error and the entire contents of the configuration memory (EEPROM) flew out, i.e. injection coding, immobilizer code, mileage, gearbox configuration. But this is not a problem in this Fiat, after switching on the ignition the immobilizer paired with the BCM itself and the engine started (except that in the emergency mode and hardly under the bonnet it did not jump out on unencrypted CR injections).

Of course, the order of disconnecting / connecting with the clamp is completely irrelevant to electronics, it is only about the safety of the person who does it.

There is another probable scenario - damage to the memory content due to a large voltage drop when trying to start on a discharged battery and / or when it crashes when disconnecting / connecting the battery. Often the problem is incorrect disarming of the alarm (especially unmanned).

tzok wrote:

There is one more likely scenario - memory damage due to a large voltage drop when attempting to start on an empty battery

It's unlikely - it shouldn't happen.

tzok wrote:

or at the time of sparking when disconnecting / connecting the battery

This, in turn, is the most likely.

tzok wrote:

Often the problem is incorrect disarming of the alarm (especially unmanned).

And that would say that probably the most real cause of the whole fault.

robokop wrote:

It's unlikely - it shouldn't happen.

It shouldn't but maybe. If the battery is sulphated and the voltage will drop and rise, the microcontroller can do various "miracles". The BOD system may not react properly in such a situation, in total from the point of view of uK it is a situation similar to sparking power cables, only the frequency of "chaff" much lower.

tzok wrote:

It shouldn't but maybe. If the battery is sulphated and the voltage will drop and rise, the microcontroller can do various "miracles".

Stop. How many such cases have you seen in the VAG group? Every winter there would be a Skód / VW discharge with unused drivers. Everything can, including the landing of a UFO. Why make fantastic hypotheses, since you don't really know what the dear author was doing, in addition to replacing the battery. Stupid errors can even be caused by the scorched body mass.

I see that the topic has gone down to the secondary threads, I refresh.
The alarm is 100% disarmed.
The situation is that I am turning the starter for the first time and after 3 seconds of shooting a single ignition appears on one of the cylinders. On the second attempt, the immo key indicator lamp flashes and the car lights up for a second.
Errors in immo and driver are the same. Immo does not accept VCDS attempts to delete / add keys. Any ideas?

While playing with the battery, you moved the cables - somewhere rotted the mass lead / eyelet, fuses on the battery, loose clamp, and finally a damaged battery. I am already skipping a slip-up polarity mishap or mixing controllers' loads with some strange diagnostic device.