What are the possible causes of the P1299 code in a Ford F150?
- Low coolant level
- Faulty thermostat
- Faulty cylinder head temperature (CHT) sensor
- Cylinder head temperature sensor harness is open or shorted
- Poor electrical connection in the cylinder head temperature sensor circuit
How to fix the P1299 code in a Ford F150?
Start by checking the “Possible Causes” listed above. Visually inspect the wiring harness and associated connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
What are the possible symptoms of the P1299 code in a Ford F150?
- Check engine light on (or Service Engine Soon warning light)
What does the P1299 code mean in a Ford F150?
The cylinder head temperature (CHT) sensor is a thermistor device where resistance changes with temperature. The electrical resistance of a thermistor decreases as temperature increases, and resistance increases as temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the Powertrain Control Module (PCM) corresponding to temperature.
The CHT sensor is installed in the aluminum cylinder head and measures the metal temperature. The CHT sensor can provide comprehensive engine temperature information and can be used to infer coolant temperature. If the CHT sensor transmits an overheating condition to the PCM, the PCM initiates a fail-safe cooling strategy based on the CHT sensor information. A cooling system issue such as low coolant level or coolant loss can cause overheating. As a result, damage to major engine components could occur. Using both the CHT sensor and the fail-safe cooling strategy, the PCM prevents damage by allowing engine air cooling and backup capability.
The Diagnostic Trouble Code (DTC) indicates that an engine overheating condition was detected by the cylinder head temperature sensor. A Failure Mode Effects Management (FMEM) strategy called fail-safe cooling has been activated to cool the engine.