Stop-start system not working in cold weather

Actually, Cold weather can strain the battery, making it less capable of supporting the stop-start function. This is a common problems in many cars including Mazda CX-3. This happens because in cold weather the battery's efficiency and capacity is reduced reduced. To resolve this, you need to make sure the battery is in good condition and fully charged. Using a battery warmer or insulation can help over come this issue during cold season. Sometimes thickened engine oil can also impede engine performance, and the system might disable itself to maintain cabin temperature if the heater is heavily used. Use the recommended oil for cold weather, and minimize excessive use of climate control

The stop-start system in your Mazda CX-3 helps to save fuel by turning off the engine when you're stopped. If it's not working in cold weather, it might be due to a weak battery. Check if the battery terminals are corroded, like rusty connections. Or perhaps the system's sensor is faulty, which could be the thermostat that's not reading the temperature correctly. You might also need to check the battery's age and condition. If it's old, you need to replace it. Make sure to clean the terminals or replace the sensor. Another issue could be low fuel pressure, which can actually prevent the system from working. If you could check these properly, it should fix the issue.