Adam No Start

Sounds frustrating. I had a similar issue with my old Renault Megane – it wouldn't start and displayed a generic engine fault. The cable connections of the battery were the culprit. It can be so simple. The Engine Control Unit (ECU), sometimes called Engine Control Module (ECM) is basically the car's computer that controls the injection or the ignition. The OBD reader failing to connect also points towards a power or communication issue with the ECU. Before assuming the worst, double-check the main power supply and grounding to the ECU. Have you checked all the cable connections?

Battery connections, you say? I haven't given them a super thorough look. When you say 'cable connections', are we talking just the main terminals on the battery itself, or are there other grounding points I should be hunting for? And how did you diagnose it on your Megane – did you also have issues connecting to the ECU with a diagnostic tool?

Yes, I had the same issue with the diagnostic tool. Couldn't connect at all. I'd check both the main terminals for corrosion and tightness and trace the ground cable from the battery to the chassis. Make sure that connection is clean and tight as well. There are also usually other grounding straps from the engine to the chassis – check those too. If those connections are not good, the Engine Control Unit doesn't work as expected and the engine doesn't start. If all that checks out okay, then it might be time to consult a workshop to rule out deeper issues.

Well, you were spot on! I gave those battery cable connections a proper scrub and tightened them up, and she fired right up! Apparently, they weren't "good". Cost me 155€ at the workshop. That's a lesson learned! Thanks a million for the tip! You've saved me a fortune and a ton of grief. I was really fearing an expensive ECU replacement!