Coolant Temperature Sensor
2019 Jeep Wrangler · 3.6L V6
Sensor Type
thermistor
Waveform Type
dc-variable
Location
Front of engine block, near thermostat housing on passenger side of the 3.6L Pentastar V6
Pins
2-pin connector
Timebase
1s/div or 5s/div for temperature sweep testing
Voltage Scale
1V/div
Trigger
Not applicable for DC signal
Wiring
Black/Light Blue (signal) and Black/White (sensor ground)
Expected Voltage Range
At Idle
0.5V to 1.2V
At Higher RPM
0.3V to 0.8V
Expected Pattern
Smooth DC voltage that decreases as temperature increases, typical NTC thermistor behavior with 5V reference
Known-Good Waveform
At cold start (68°F), expect 2.5-3.0V. At operating temperature (195-205°F), expect 0.5-0.8V. Voltage should drop smoothly and linearly as engine warms up with no sudden jumps or dropouts. Reference voltage should be stable 5V.
Common Failure Patterns
Voltage stuck at 4.8-5.0V regardless of temperature
Cause: Open circuit in sensor or wiring, broken thermistor element
Voltage reads 0V or near 0V
Cause: Short to ground in wiring or internally shorted sensor
Related DTCs: P0117
Erratic voltage readings or sudden spikes
Cause: Corroded connector pins, poor ground connection, or failing thermistor
Related DTCs: P0116
Diagnostic Tips
Use a heat gun to verify sensor response - voltage should drop smoothly as temperature increases. Check for coolant intrusion in connector which is common on Pentastar engines. Resistance should be approximately 2400-2700 ohms at 68°F.
Related Diagnostic Trouble Codes
P0115P0116P0117P0118P0119
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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