P0112

DTC P0112 Intake Air Temperature (IAT) Sensor I Circuit Low Voltage

Circuit Description

The intake air temperature (IAT) sensor 1 is fitted between the air cleaner and turbocharger. It is internal to the mass air flow (MAF) sensor. The IAT sensor 1 is a variable resistor and it measures the temperature of the air entering the engine. The sensor has a signal circuit and a low reference circuit. The ECM supplies 5 volts to the signal circuit and a ground for the low reference circuit. When the IAT sensor 1 is cold the sensor resistance is high. When the air temperature increases the sensor resistance decreases. With high sensor resistance the ECM detects a high voltage on the signal circuit. With lower sensor resistance the ECM detects a lower voltage on the signal circuit. If the ECM detects an excessively low signal voltage this DTC will set.

Condition for Running the DTC

- DTC P0113 is not set.
^ The battery voltage is more than 7 volts
^ The ignition switch is ON.

Condition for Setting the DTC

^ The ECM detects that the IAT sensor 1 signal voltage is less than 0.1 volts for 3 seconds Action Taken When the DTC Sets
^ The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type A.
^ The ECM uses an IAT substitution of default value.
^ The ECM inhibits EGR control.
^ The ECM inhibits DPF regeneration control.

Condition for Clearing the DTC

^ Refer to DTC Type Definitions for Condition for Clearing the MIL/DTC - Type A.

Diagnostic Aids

^ If an intermittent condition is suspected refer to Intermittent Conditions in this section.
^ Use the Temperature vs. Resistance table to test the IAT sensor 1 at various temperature levels to evaluate the possibility of a skewed sensor. A skewed sensor could result in poor driveability concerns.

Circuit/System Testing DTC P0112