Tiburon No Start

A weak battery connection often causes no-start issues, especially with modern ECUs. The ECU needs stable voltage when cranking. If the voltage drops too low because of bad connections, the ECU might not start up right, stopping the engine from starting. Have you load-tested the battery? What voltage do you see at the battery terminals when it's resting and when you try to start it?

I haven't done a load test yet, but the voltage is 12.6V at rest. When I try to start it, the voltage drops to about 10.8V. Could this drop cause the ECU to fail, even if it seems okay? Also, what tests should I do to find connection problems, like measuring contact resistance?

10.8V when cranking might be too low. Even if the voltage comes back up, the drop could mess up the ECU's startup. Before blaming the ECU, clean and tighten the battery terminals and check the ground connections to the chassis and engine block. A connection with high resistance can still pass voltage but fail when under load. If the problem continues after checking the connections, take it to a workshop for a full checkup.

Thanks for the help. I cleaned and tightened all the battery cable connections. Now the engine starts fine. Contact resistance measurements showed high values at the negative terminal connection. The diagnostic confirmation and terminal fix cost 155€. Thanks again for pointing me to this simple but important step.