P1290 Code MAZDA Possible Causes
- Faulty thermostat
- Overheated engine
- Low coolant level
- Faulty Cylinder Head Temperature (CHT) sensor
- Cylinder Head Temperature (CHT) sensor harness is open or shorted
- Poor electrical connection in the Cylinder Head Temperature (CHT) sensor circuit
How is the P1290 MAZDA Code Repair Done?
Start by checking the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
When is the P1290 MAZDA Code Detected?
The Engine Control Module (ECM) detected the cylinder head temperature below expected values
What are the Possible Symptoms of P1290 MAZDA Code?
- Check Engine Light On (or Service Engine Soon warning light)
What Does the P1290 MAZDA Code Mean?
The Cylinder Head Temperature (CHT) sensor is mounted in the cylinder head wall and is not connected to any coolant passages. The CHT sends a signal to the Powertrain Control Module (PCM) indicating the cylinder head temperature. If the temperature exceeds 126°C (258°F), the PCM shuts off four fuel injectors at a time. The PCM will alternate the four disabled injectors every 32 engine cycles. The four cylinders that are not injected with fuel act as air pumps to help cool the engine. If the temperature exceeds 154°C (310°F), the PCM shuts off all fuel injectors until the engine temperature drops below 154°C (310°F).