Coolant Temperature Sensor
2023 Ford F-150 · 3.5L V6 EcoBoost
Sensor Type
thermistor
Waveform Type
dc-variable
Location
Mounted on the engine coolant crossover tube between the cylinder heads, passenger side of engine
Pins
2-pin connector
Timebase
1s/div or 5s/div for warm-up monitoring
Voltage Scale
1V/div
Trigger
Not applicable for DC signal
Wiring
Red/White wire (signal) and Black wire (sensor ground)
Expected Voltage Range
At Idle
0.4V to 0.8V
At Higher RPM
0.3V to 0.6V
Expected Pattern
Smooth DC voltage that decreases as temperature increases, negative temperature coefficient thermistor
Known-Good Waveform
At cold start (68°F), expect approximately 2.5-3.0V. As engine warms to operating temperature (195-220°F), voltage should smoothly decrease to 0.4-0.8V. The transition should be gradual without sudden jumps or dropouts, taking approximately 5-8 minutes to reach full operating temperature.
Common Failure Patterns
Voltage stuck at 4.8-5.0V regardless of temperature
Cause: Open circuit in sensor or wiring, broken thermistor element
Voltage reading 0V or near 0V
Cause: Short to ground in wiring or internally shorted sensor
Related DTCs: P0117
Erratic voltage with spikes or sudden changes
Cause: Corroded connector pins, intermittent wiring connection, or contaminated sensor
Related DTCs: P0116
Diagnostic Tips
On EcoBoost engines, verify coolant level first as low coolant can cause erratic readings. The PCM uses a 5V reference with internal pull-up resistor; verify 5V reference at connector when unplugged. Resistance should be approximately 37k ohms at 68°F and 2.2k ohms at 195°F.
Related Diagnostic Trouble Codes
P0115P0116P0117P0118P0119
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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