Hi guys, past week have been having trouble starting my golf. Would crank and turn over, just struggled but once the car was running, drove smooth and boosted just like normal. Thought it was 100% just a fried battery as I had stupidly let it run dead a fair handful of times in the past month and had it jump started. Got the old battery tested - was confirmed to be dead. Bought a new battery popped it in and to my surprise, got nothing on key turn. No crank, didn't even try. Electronics showed on dash, radio worked, lights worked, windows etc - but engine didn't want to start. Didn't seem to hear any clicking either which I understand can be a problem with the starter motor - all I could hear was a long beep noise in the engine that would go away 5secs ish after taking the key out. I have a little diagnostics reader so I ended up plugging that In and I got two fault codes, one was to do with turbo/supercharger underboost - which I believe is because I have a stage 2 ECU tune without gearbox tune, was told by tuner this would be fine but the gearbox would stop it boosting as much as it should at certain revs. The other fault code was 005634 and looking into this its all to do with voltage being too low. I also checked some other things in the reader, such as cent electronics, and some of them returned voltage fault codes. Supply voltage. Voltage too low. Etc. Has anyone experienced an Issue like this? Any help would be appreciated as this is my first golf and I love driving the car.
