F 150 Heritage 4WD Pickup V8-5.4L CNG VIN M (2004)
Engine Temperature Sensor: Description and Operation
CHT Sensor
The cylinder head temperature (CHT) sensor:
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is mounted into the wall of the cylinder head and is not connected to any coolant passages.
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sends a signal to the PCM indicating the cylinder head temperature.
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if the temperature exceeds 126°C (258°F) 5.4L, 130°C (265°F) 4.6L, the PCM disables four fuel injectors at a time. The PCM will
alternate which four injectors are disabled every 32 engine cycles. The four cylinders that are not being fuel injected act as air pumps to
aid in cooling the engine.
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if the temperature exceeds 154 °C (310°F) 5.4L, 166°C (330°F) 4.6L, the PCM disables all of the fuel injectors until the engine
temperature drops below 153°C (308°F) 4.6L, 154°C (310°F) 5.4L.
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DTCs are set.
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If the engine reaches critical temperature, the following happens:
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The coolant temperature gauge pointer will read fully hot at 121°C (250°F). The check gauge warning indicator will illuminate.
