p0126
Moderate
Mazda · Sedans
Insufficient Coolant Temperature for Stable Operation
Quick Answer
Error code P0126 on your Mazda Sedans means: Insufficient Coolant Temperature for Stable Operation. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
NCBLGHSE
Likely Causes
  1. Thermostat stuck open
  2. Faulty coolant temperature sensor
  3. Engine cooling fan running constantly
  4. Water pump failure
  5. Coolant level too low
How to Fix It
1
Check coolant level and top off if needed
2
Monitor engine temperature gauge
3
Feel radiator for temperature balance
4
Test coolant temperature sensor
5
Replace thermostat if necessary
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Coolant
Thermostat
Temperature sensor
Related Error Codes
Video Guides
Loading video guides…
Search more on YouTube →