What is the P0118 fault code Engine Coolant Temperature (ECT) Sensor Circuit High Input failure description? How do you fix the P0118 fault code What are the causes and symptoms of the P0118 error code?
What is the P0118 fault code? What does it signify?
A thermistor is used to measure engine coolant temperature (ECT). It is screwed into coolant passage in the head. When coolant temperature drops, the sensor resistance will be high. The resistance decreases as the coolant temperature rises.
The powertrain controller module (PCM), provides a 5V reference signal and a ground circuit to the sensor. This signal is used by the PCM to monitor coolant temperature. After the engine has run for a few minutes, if the PCM detects that the ECT sensor voltage signal is too high (more than 4.91 volts or less than -40°C) or outside of the preset values, a code P0118 will be triggered.
There are many vehicles that fall prey to the P0118 fault code, including models from Honda, Dodge and Volvo, Jeep, Volkswagen.
What causes the P0118 Fault code?
Here are some reasons why P0118 should be set.
- – Defective engine coolant temperature (ECT) sensor
- – Broken wires or loose connections to the ECT sensor Circuit
- – Short or open circuit in ECT Sensor Ground Wire
- – Defective PCM
What are the symptoms for P0118 malfunction code?
You may experience the following symptoms if your vehicle has a code of P0118:
- – Illumination at the check engine lights
- – When the engine is cold, it runs hard
- – Engine can run erratically, misfire or hesitate until it is warmed up
- After the engine heats up, it should start to run about as normal.
- – An increase in fuel consumption
- – Exhaust fumes emitting black smoke
- – The PCM goes into fail-safe mode and stabilizes the engine coolant temperature at 80°C / 176F.
Note: P0118 symptoms can vary depending on the PCM strategy used by the vehicle manufacturer.
How do I fix the P0118 fault code?
- First, all codes must be cleared. The vehicle will then be retested to see if the codes return.
- ECT sensor wiring, connectors and repair or replacement
- Troubleshooting an open or short circuit in ECT sensor ground wire
- – Replacing faulty ECT sensors
How Serious Is the P0118 Fault Coding?
Code P0118 places the PCM into fail-safe mode. This can cause the engine’s to run erratically, or to hesitate until it warms up. The manufacturer may have a strategy to prevent vehicles from entering failsafe mode. This can lead to excessive fuel consumption, engine component carbon pollution, and other driving problems. It may be given additional treatment if the vehicle is left in failsafe mode for extended periods to correct ignition problems and remove carbon deposits.
