Hilux uneven idle defective engine mount

That does sound concerning. I'm no expert, but a defective engine mount could definitely cause those symptoms. When you say 'faulty cable or plug connection,' have you checked the connections yourself? Are there any visibly loose or damaged wires around the engine mount area?

I did a visual inspection of the cable and plug connection. I didn't see any obvious damage, but I don't have the tools for a full diagnostic. Could a slightly damaged connection still cause this, even if it's not visibly broken?

Absolutely, a slightly damaged connection could very well be the culprit. Sometimes, even a hairline crack or corrosion inside the connector can disrupt the signal and trigger the error. Given the symptoms and error code, and the fact that you are uncertain, it would be best to have it checked at a workshop.

I took the Hilux to a mechanic based on that advice. They confirmed the engine mount was defective due to the cable connection. The repair was 95€ including parts and labor. Thanks for the help.