P0118 Mercury Code - Engine Coolant Temperature Sensor 1 Circuit High
Quick Answer
The Engine Coolant Temperature (ECT) Sensor is a thermistor device in which resistance changes with temperature. Common causes include Low engine coolant level, Faulty Engine Coolant Temperature (ECT) Sensor, Faulty engine coolant thermostat. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0118 Mercury indicates Engine Coolant Temperature Sensor 1 Circuit High.
- Common causes
- Common causes include Low engine coolant level, Faulty Engine Coolant Temperature (ECT) Sensor, Faulty engine coolant thermostat.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0118 Mercury Description
Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider network so varying the resistance of the passive sensor causes a variation in total current flow. The voltage that is dropped across a fixed resistor (pull-up resister) in series with the sensor resistor determines the voltage signal at the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.
The ECT Sensor is located in an engine coolant passage and measures the engine coolant temperature. The PCM uses the engine coolant temperature input for fuel control and for cooling fan control. The ECT Sensor can be a threaded or twist lock type.
This Diagnostic Trouble Code (DTC) is set when the ECT Sensor signal is greater than the self-test maximum. The ECT Sensor signal maximum is -50° C (-58° F).
What are the Possible Causes of the DTC P0118 Mercury?
- Low engine coolant level
- Faulty Engine Coolant Temperature (ECT) Sensor
- Faulty engine coolant thermostat
- Engine Coolant Temperature Sensor harness is open or shorted
- Engine Coolant Temperature Sensor circuit poor electrical connection
How to Fix the DTC P0118 Mercury?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0118 Mercury code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P0118 Mercury Code
1. What does the OBDII code P0118 mean for a Mercury vehicle?
P0118 indicates that the Engine Coolant Temperature (ECT) Sensor 1 circuit is reading a voltage that is abnormally high, suggesting a potential issue with the sensor or its circuit.
2. What are the common symptoms of the P0118 code in a Mercury?
Symptoms may include the check engine light being illuminated, poor fuel economy, rough engine operation, difficulty starting, and a temperature gauge that doesn't work properly.
3. What causes the P0118 code on a Mercury?
Common causes include a faulty ECT sensor, damaged or corroded wiring, a poor electrical connection, or a problem with the vehicle’s PCM (Powertrain Control Module).
4. Can a faulty thermostat trigger the P0118 code?
No, a faulty thermostat does not directly trigger P0118, but it can affect engine temperature readings. The code typically points to an electrical issue with the ECT sensor circuit.
5. How do you diagnose the P0118 code on a Mercury?
Diagnosis may involve checking the ECT sensor and its wiring, testing the sensor’s resistance, inspecting the electrical connectors, and using a scan tool to monitor live temperature data.
6. Can I drive my Mercury with the P0118 code active?
Driving with P0118 is not recommended as it can lead to poor engine performance, reduced fuel efficiency, and potential overheating due to inaccurate temperature readings.
7. How do you fix the P0118 code in a Mercury?
Repairs may include replacing the ECT sensor, repairing damaged wiring, cleaning corroded connectors, or, in rare cases, replacing the PCM if it's faulty.
8. How much does it cost to fix the P0118 code on a Mercury?
The cost varies depending on the issue, but replacing the ECT sensor typically costs $50-$150, while wiring repairs or PCM replacement can be more expensive.
9. Can extreme weather conditions cause the P0118 code?
Extreme cold or heat can sometimes affect sensor operation, but the code is usually due to an electrical fault rather than environmental conditions.
10. How can I prevent the P0118 code from occurring again?
Regular maintenance, including inspecting wiring and connectors, replacing sensors as needed, and ensuring proper coolant levels, can help prevent future occurrences.
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