Mitsubishi ASX 2020 Problems

There are several things that could be causing a loss of power on really hot days, but a prime suspect would be an engine that is getting too hot. When that happens, the car will often go into limp-home mode which is usually signalled by a loss of power and a check-engine light illuminating (the precise symptoms you’re seeing).

The air conditioner consumes quite a bit of engine power when its working, and this extra load might be the tipping point for the car starting to overheat. When you switch it off, the engine can relax a little and the temperature falls. So the advice would be to have the car’s cooling system checked. It could be low on coolant or have a faulty pump, hose or thermostat. While you’re at it, have the car electronically scanned to see if any fault codes have been recorded, as this will also help your mechanic diagnose the issue.