Slava

Thanks to all guys, I solved the problem. First of all, personal and huge thanks to you, @Wino. Schemes do the trick: The fuel pump relay is not the only one who controls the pump. Another relay (called also Simos control unit relay). So that another relay (number 429) is the one who does that first initial start of the pump. And it works not stable. Changing that relay solves the problem. Thank you very very much. If you can - please mark the topic as "solver" or "resolved"

The most strange thing: If I add contact negative ( earth ) signal on ECU PIN 26 ( negative wire for fuel pump relay) just only when the starter is working - and then release it as it is (without additional negative supply on that wire) - everything works perfect. What the hell is going on with this car?

So, What I have for today: Checking wires, I found that the Hall sensor (page 2/9, element G40) must have +5V on black-white wire. While red-blue one with "-". I double-checked it in different states (with ignition, without, with engine started) - both have "-". I checked wires for cut - everything looks good. How I check it: - I put multimeter PIN red to black-white, PIN black to red-blue - no any voltage. - I put multimeter PIN red to black-white, PIN black to accumulator "+" - and see "almost -6v", which means that there is a voltage there. Is that correct approach? I also checked same with another ECU, but there is an issue with immobilizer with it. So, I can't start engine with it, but the parameters are same - no +5V on G40. Are these steps correct? thanks

many thanks all of you guys. I've got how to read those numbers - thanks Wino. So, right now I started from beginning as planned. Will keep you updated.

What that bottom values mean? here is 57, 58, 59 etc... ? And another question - you wired numbers like 68 and 59. I'm assuming that this is just an example, and I have to ignore numbers, because in real situation the 59 number will be connected to 59 and 68 will be connected to 68, right?

Ok. I got it. It's a 'reference' - which means, somewhere later I can find same value and it will mean that fuel pump relay link #36 wired with this one. right?

Ok. I bought those materials, and I think it would be easier to start from beginning. Today Im going to reset all codes once again, and using multimeter and those schemas I would like to start from relay, checking sensors (is there supply oprovided), and I'll try to check the resistance of those sensors. Maybe I will find something. One more question - could you please share description, how to read schemas? for example, I can't understand, what those numbers mean, for example, for fuel pump relay scheme - yellow-black wire described as '85' which is number of relay contact, then I see '6' exact in same place (no idea what does it mean), then I see 0.5 in the middle of this wire - which is the size of the wire I think, and then I see '36' in some borders like square. Looks like this is the PIN nub,er of ECU, but I'm not sure.

please share a link.

Could you please share electrical schemes for my car please?

What do you think - could it be just immobilizer issue? . I mean generally - could immobilizer blocks all of that supply?

Hi. So, today I tried to check other sensors around the engine - found one (probably, temperature sensor, with brown and white wires), it has just 0.6V when I start the engine. Is that ok? 2 PIN connector - brown and white.

Thank you for your time. Waiting for your findings. I don't have any schemes, any documentation or anything that might help me at the moment.

So it really looks like that the ECU decides not to go to ignition state: no supply on cam sensor, no supply to fuel pump relay.

Yep. 64 pin has connection to white-black +5V pin on sensor. And 54 pin GROUND has connection to blue-brown, but the blue-brown is wired with few brown wires inside the trunk, so it joined with just brown, which comes to 54. Is that a factory-connection? Or additional wiring by other guys? Not sure. Anyway, the connection is present, but there is no supply on sensor. Could it be some immobilizer issue?

I can't upload files anymore. but this might be what we are looking for: CHFA LNR

Not sure about the code you mean. It's 1.2 petrol HTP (Volkswagen). Do you need other specific code? if so - how can I get it?

I've just checked the CMP (camshaft position sensor) and there is no any voltage there even during start. Could it be the reason? IMG_3826.MOV

No. I tried to start a car with restored original wiring first. potentially, it might be same issue with ECU. But the chance that both ECUs with the same problem is a very low i think

the most strange thing is that the ECM does not provide 0V on that blue-yellow wire. That's make me confused most. Btw, VIN code is TMBEA25J2B3025628

So, I attached the audio connector with all additional wires. The brown one (with cut) is the one, where ground signal from relay was wired (find blue-yellow wire in photo with blue-purple socket for relay, last one in previous post). the white-black is the one, which comes from broken RED wire (ignition) from fuse box. (find red broken wire on first photo in previous post. Also, it is the same on third photo - it comes on fuse with '10' in bottom line).

Hi folks! Im owning Skoda Fabia 1.2 HTP 2010, and when I bought it - the 'Check Engine' light was on. So, official dealer's service guy said, that it might be a fuel pump issue. ( and it sounds reasonable since this car was upgraded to LPG. Usually people run car with empty fuel tank using LPG only, so fuel pump got damage). But, once I start to investigate the problem - it becomes more and more interesting. First of all - I found the additional wire, that wired into the Positive 12V ignition wire (see attached image, red repaired wire). I have no idea, what is it for, but the additional wire then goes to audio system connector. I don't think it makes any sense for fuel pump issue. More interesting thing is that I found additional wire from fuel pump relay ground wire - to ground in audio. What I found now is that when the ignition is ON (key in position 3, but the starter is not working now), we are getting ground on audio system. That means, that relay will be turned ON. But if I try to check the original ground wire on relay - there is no any signal. No ground, no +12V, nothing. That drives me to the idea that my ECM (ECU) died. So, I tried to replace it. But that made no any sense - the problem is the same. I double-checked all wires - all looks good. I also tried to check all fuses, I checked fuel pump (actually, I replaced it), and I also checked relay. So in a short: I have p0230 Fuel Pump relay circuit issue, all fuses are ok ECU (ECM) tested by replacing to another. The symptom is: no Ground signal on fuel pump relay, no ground signal on the same PIN in ECU (ECM). For me it looks like the algorithm of the ECU decided not to start the fuel pump, which means that 'no ground' state is a predictable and expected. But why? maybe that is some sensor fault or something else? Anyway, I'm waiting for your comments , also I will be happy for full step-by-step description of how ECU starts the fuel pump. Thank you all.