P0118 – OBD-II DTC

OBD-II DTC P0118 – Engine Coolant Temperature Circuit High Input

DTC P0118 meaning

DTC P0118 refers to a diagnostic trouble code indicating a high input signal from the Engine Coolant Temperature (ECT) sensor. This code is triggered when the Engine Control Module (ECM) detects that the voltage from the ECT sensor is higher than the expected range. The ECT sensor plays a crucial role in monitoring the engine’s temperature, which is essential for optimal performance and emissions control.

DTC P0118 symptoms

Common symptoms associated with DTC P0118 may include:

• Illuminated check engine light
• Engine overheating
• Poor fuel economy
• Rough engine performance
• Increased emissions

DTC P0118 causes

Several factors can lead to the triggering of DTC P0118, including:

• Faulty Engine Coolant Temperature sensor
• Wiring issues, such as short circuits or damaged connectors
• Faulty Engine Control Module (ECM)
• Corrosion or poor connections in the ECT sensor circuit
• Incorrect coolant levels or types

DTC P0118 seriousness

DTC P0118 is considered a serious issue as it can lead to engine overheating and potential damage. If the engine runs too hot, it may cause severe internal damage, leading to costly repairs. Additionally, the vehicle may experience poor performance and increased emissions, which can affect drivability and compliance with environmental regulations.

How to diagnose DTC P0118

To diagnose DTC P0118, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P0118 code.
2. Inspect the ECT sensor and its wiring for any visible damage or corrosion.
3. Check the coolant level and ensure it is at the proper level.
4. Test the ECT sensor’s resistance with a multimeter to ensure it is within specifications.
5. Examine the ECM for any faults or updates that may be necessary.
6. Clear the code and perform a test drive to see if the code reappears.

How to fix DTC P0118 step-by-step instructions

To fix DTC P0118, follow these step-by-step instructions:

1. Ensure the engine is cool and disconnect the battery.
2. Locate the Engine Coolant Temperature sensor and inspect it for damage.
3. If the sensor is faulty, replace it with a new one.
4. Check the wiring and connectors for any signs of wear or corrosion repair or replace as necessary.
5. Reconnect the battery and clear the DTC using an OBD-II scanner.
6. Start the engine and allow it to reach operating temperature while monitoring the ECT readings.
7. Perform a test drive to ensure the code does not return.

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