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"

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.