My Optra 2005 needed to be repaired because the timing belt was broken and some valves were twisted, among other problems. Some days after this big repair, the engine light (MIL-check engine) turned on, but the car continued working without any failures. What might be happening? Thanks in advance for your help.

Hi everyone. This is what happened to my car. Two days after repairing the whole engine, the hold light started blinking on the dashboard and the battery got damaged. I changed the stop neutral sensor myself and removed the battery for it to be repaired. When installing it back, a noise of a short circuit was heard, even though there was no smoke coming out from nowhere. Since that moment, speeds have no longer been indicated on the dashboard and the car has not started working again. Even though the engine starts running, it won't finally turn on. I've already changed the crankshaft sensor but with no positive results. Hope you can help me solve the problem, thanks.