Error Code P0118: What It Means & What To Do?

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The OBD code P0118 can be defined as an engine coolant temperature circuit high input. This fault code would indicate a high voltage input from the coolant temperature circuit to the powertrain control module.

This fault code refers to the engine coolant temperature sensor. Here the ECT is a thermistor and it is located in a coolant passage in the cylinder head. Its main job is to monitor the rise and fall of engine coolant temperature. If the sensor is operating normally, then it would mean that the resistance would be high when the coolant temperature is low and the resistance would drop when the coolant temperature increases.

What causes this problem with the Engine Coolant Temperature Circuit High Input?

• There can be a poor connection at the sensor
• An open in the ground circuit between the ECT sensor and the PCM
• There can be a short in the voltage feed between the sensor and the PCM
• There can be some issues in the powertrain control module
• A faulty temperature sensor

1. Engine Coolant Temperature Sensor - A faulty ECT Sensor can be troublesome. You can always rely on us as we have best ECT Sensor for our customers.
2. Engine Wiring Connector - If everything is alright with PCM, then there is surely some defect in Engine Wiring Connector. Get it replaced before the situation gets worse.
3. Powertrain Control Module - Are there some faults in your Powertrain Control Module? Don’t waste time and get them replaced or else P0118 code can turn up.
4. Engine Control Module - Everything is fine with turbocharger/supercharger and still P0118 code triggering? Then you must get your Engine Control Module checked.
5. Air Fuel Ratio - There can be some issues with the Air Fuel Ratio due to which you may see P0118 code appearing over and over again. Visit us to buy best quality Air Fuel Ratio online.
6. Fuel System - A lot of issues can arise do to defective Fuel System. Did you just see P0118 code flashing? Now you know the reason why it is appearing. Get it inspected and replaced on time.

We care for our customers and that’s why we can totally understand your problem. That’s the reason why we have listed out some major symptoms behind the flashing up of OBD Code P0118. They are mentioned here as follows:

Common Symptoms

• The check engine light would be turned on by the engine control module and goes into failsafe mode, this would substitute input to 176 deg F
• A hard start may be experienced by the engine when it is cold, and would start normally when warm.
• The engine can start running roughly and would hesitate until the engine actually warms up
• The car engine should run close to normal once the engine warms up

• You must repair or replace the IAT connector to fix shorts or the open circuit that are caused by corrosion
• The wiring should be repaired or replaced if necessary to fix shorted or open circuits in the harness
• The IAT sensor should be replaced with a new sensor 

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• The disconnected sensor connectors or damaged connectors should be inspected
• Make sure that you scan and document the codes received and views the freeze frame data to see when the code was set
• The OBD-II fault codes should be cleared and retest the system to see if the code comes back
• The sensor connector should be disconnected and inspect for corrosion or bent pins and repairs as per the requirement
• The two connector pins should be connected together to see if the output on scanner shows above 284 deg F, which would indicate that the wiring is okay, and replace the ECT sensor
• Above 284 deg F, the circuit has an open circuit in the wiring, connector or ECM and will be fixed by the technician

Common Mistakes When Diagnosing The P0118 Code

• Not performing a visual inspection of connections and wiring can be a big mistake
• You must follow the manufacturer pinpoint test procedure step-by-step and should not skip any steps
• You should replace an IAT sensor only when tests indicate a problem
• Make sure that you connect a new or known good sensor to the harness and viewing the ECM data to see if the temperature output from the sensor is as expected