Why does the car show a transmission fault warning during a cold start, but it goes away after waiting and restarting?

My Volvo S40's battery seems fine. Why does the electrical system show a fault, and it starts smoking as soon as I start it? We've checked but can't find what's wrong.

Hey folks, does anyone with a Multivan experience this? When starting from a cold engine, there's a huge vibration coming from the rear. The noise is really loud, but it goes away once the RPM drops. Does anyone know what's going on?

Is it normal for the Yizhi to have an RPM of 2500 during a cold start in the morning?

Is there an issue with the electrical system in the 2017 MG GS automatic model, as it shows faults during summer after two years of use?

Why does the transmission often show a fault code and then disappear on its own shortly after?

Why does the car show a transmission fault warning during a cold start, but it goes away after waiting and restarting?

The 2014 Zhiya's Blind Spot Detection (BIUS) system showed a fault warning in July this year, but today the fault disappeared and the feature is working again. What could be the reason?

Why is my 2018 1.6 manual transmission car having unstable idle when cold started?

When I start my 2021 Outlander, there's a popping sound in the engine bay during cold starts, but it goes away once the temperature rises. Has anyone else experienced this?

I have a Haima S5 with an automatic transmission, and occasionally the transmission warning light turns on. But when I press the brake, it goes off! When I try to read the error code, nothing shows up. What could be the reason?