P1115 MERCURY Possible Causes
- Faulty Intake Air Temperature Sensor 2
- Intake Air Temperature Sensor 2 harness is open or shorted
- Poor electrical connection in the Intake Air Temperature Sensor 2 circuit
- Damaged Powertrain Control Module (PCM)
How to Fix Code P1115 MERCURY?
Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
What Does It Mean?
Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with a mass air flow sensor cleaner. Reset the code and drive the vehicle. If the code returns, it may be necessary to replace the mass air flow sensor. Monitor the IAT on a scan tool. Look for sudden changes in the reading when the harness is shaken or the sensor is tapped.
Possible Symptoms
Check Engine Light illuminated (or Service Engine Soon warning light)
P1115 MERCURY Meaning
The IAT sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases and the resistance increases as the temperature decreases. The variable resistance affects the voltage drop across the sensor terminals and provides electrical signals to the Powertrain Control Module (PCM) corresponding to the temperature.
Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider network so that the change in the resistance of the passive sensor causes a change in the total current flow. The voltage that drops across a fixed resistor in series with the sensor resistance determines the voltage signal to the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.
The IAT sensor provides air temperature information to the PCM. The PCM uses the air temperature information as a correction factor in the calculation of fuel, spark, and airflow.
The IAT sensor provides a faster response time to temperature change than the ECT or CHT sensor.
Currently, there are 2 types of IAT sensors used, a standalone, non-integrated type and an integrated type. Both types function the same way, but the integrated type is incorporated into the Mass Air Flow (MAF) sensor instead of being a standalone sensor.