P0117 — Engine Coolant Temperature Sensor Circuit Low Input
Category: Powertrain Severity: Medium
Updated:
DTC code P0117 means: Engine Coolant Temperature Sensor Circuit Low Input. It falls under the "Powertrain" category, with an estimated severity of Medium. Common causes include shorted ECT sensor, signal wire shorted to ground and coolant inside the connector; it's worth confirming the diagnosis before replacing parts.
Possible causes
- Shorted ECT sensor
- Signal wire shorted to ground
- Coolant inside the connector
Symptoms
- Fan always on
- Hard cold starts
- Temperature gauge reading maximum
How to diagnose it step by step
- Read ECT on the scan tool.
- Unplug the sensor and observe.
- Check connector and wire.
- Replace the sensor.
How to fix it
The ECU thinks the engine is very hot. Unplug the sensor: if the reading drops to -40, replace the sensor; if not, find the short in the wire.
Estimated repair cost
$50–150 installed.
Frequently asked questions
What does DTC code P0117 mean?
Engine Coolant Temperature Sensor Circuit Low Input.
Is code P0117 serious?
Severity Medium. Not urgent, but worth diagnosing to avoid bigger damage.
Can I keep driving with code P0117?
Drive carefully and verify the actual temperature.
Related codes
P0116 P0118 P0115 P0113 P0112 P0110 P0120 P0121 P0122 P0123
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