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P0117 is a diagnostic trouble code (DTC) for "Engine Coolant Temperature (ECT) Sensor Circuit Low Output Problem". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
Engine Coolant Temperature (ECT) sensor circuit low output problem
P0117 is the OBD-II generic code that indicates the engine control module (ECM) has seen the ECT sensor output go less than 0.14 Volts or more than 140°C (284°F).
ECT sensor input to the ECM went to more than 0.14 Volts or 140°C (284°F) indicating a short circuit in sensor or wiring.
The ECT sensor or wiring is shorted.
Note: The symptoms are determined by the manufacturer failsafe ECM strategy for the vehicle during a failure and may vary between manufacturers and vehicles.
A visual inspection to check for any electrical connector, wiring or sensor issues.
The technician will scan and document the codes received and view the freeze frame data to see when the code was set.
The codes should then be reset to clear the OBD-II fault codes and retest the vehicle to see if the code comes back.
Disconnect ECT sensor, observe live data to see if readings go from over 284°F to -40°F.
If readings go to -40° F then replace the ECT sensor if not then look for shorted harness, connector or ECM.
Not following these simple steps:
Always do a visual inspection first.
The manufacturer pinpoint test procedure follow step-by-step not skipping any steps.
Do not replace an ECT sensor unless tests indicate a problem.
Before installation of the new ECT sensor, try connecting it and viewing the ECM data to see if the temperature output from the sensor is as expected.
The P0117 code will put the engine ECM to go into a failsafe mode.
The failsafe mode may cause engine to run rough and hesitate until the engine warms up to operating temperature.
Electrical cooling fans may run continuously.
The ECT sensor shorted is the most common failure.
Some failures for code P0117 other than the sensor include a harness shorting or a connector corrosion issue.
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