P1118 FORD - MANIFOLD ABSOLUTE TEMPERATURE CIRCUIT LOW INPUT
POST UPDATED IN February, 2023
P1118 Code failures by brands
Description of DTC code P1118
The IAT (Intake Air Temperature Sensor) measures the temperature of the air entering the engine. Since cold air has a higher density than hot air, it is possible to accumulate colder the hot air in a given volume, thus allowing the Powertrain Control Module (PCM) to continuously adjust the fuel to ensure an ideal air/fuel ratio.
The inlet air temperature sensor during operation reacts to the temperature of the air passing over it. Thus, it generates a signal voltage strictly related to the temperature passing over it at a certain time. Generally, these sensors have their resistance increase as the air passing over it cools down and if the opposite occurs, the resistance will decrease.
The P1118 OBDII fault code for Ford vehicle manufacturers occurs when a lower than expected signal is detected in the Intake Air Temperature Sensor circuit.
Symptoms of fault code P1118
- Check Engine lamp illuminated.
- With a cold engine, the engine is difficult to start.
- Irregularities during idling.
- Fuel consumption increases considerably.
- If the engine is cold, the acceleration is deficient.
- Catalytic converter
Causes of OBD2 P1118
The reasons why the P1118 OBD2 diagnostic code is set on Ford vehicles are:
- There may be IAT Sensor circuit wires or connectors, which have common deficiencies.
- The IAT Sensor circuit may be shorted or open.
- The Intake Air Temperature Sensor could be bad.
Possible solutions of the DTC code P1118
The steps to resolve the DTC P1118 OBDII code on your Ford are as follows:
- Consult the Technical Service Bulletins.
- With a scanner, you should monitor the available parameters of the IAT Sensor. If the engine is cold, this sensor should show a temperature lower than the engine coolant temperature. Consult the manual for the specified value, and measure the resistance of the sensor between its two terminals. If the resistance is not as indicated by the manufacturer, replace the sensor.
- If no discrepancy is found in the resistance of the IAT sensor, check all wiring and connectors for common damage. Repair it as necessary.
- Disconnect the Intake Air Temperature Sensor from the PCM and check for continuity, reference voltage, resistance, and ground. If any of these electrical values are not within specifications, proceed to make corrections as necessary.
