P0112
DTC P0112, P0113, or P0114
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0112
- Intake Air Temperature (IAT) Sensor Circuit Low Voltage
DTC P0113
- Intake Air Temperature (IAT) Sensor Circuit High Voltage
DTC P0114
- Intake Air Temperature (IAT) Sensor Circuit Intermittent
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the air in the sensor bore. The engine control module (ECM) supplies 5 V to the IAT sensor signal circuit and a ground for the IAT sensor low reference circuit. The signal varies with inlet air temperature and is displayed by the scan tool as °C (°F).
These multifunction intake air sensors share an engine control module (ECM) supplied low reference circuit:
* IAT sensor
* IAT sensor 2
* Intake Air Humidity sensor
* Barometric pressure (BARO) sensor
The multifunction intake air sensor houses the following:
* IAT sensor
* IAT sensor 2
* Intake Air Humidity sensor
* MAF sensor
* BARO pressure sensor
Conditions for Running the DTCs
P0112, P0113, and P0114
* The ignition is ON, or the engine is running.
* The DTCs run continuously when the above conditions are met.
Conditions for Setting the DTC
Note: The scan tool display range is between -40 and +150°C (-40 and +302°F).
P0112
The ECM detects that the IAT sensor signal is warmer than 149°C (300°F) for at least 5 s.
P0113
The ECM detects that the IAT sensor signal is colder than -60°C (-76°F) for at least 5 s.
P0114
The ECM detects that the IAT sensor signal is intermittent or has abruptly changed for at least 5 s.
Action Taken When the DTCs Set
* DTCs P0112, P0113, and P0114 are Type B DTCs.
* The ECM commands the cooling fans ON.
Conditions for Clearing the DTCs
DTCs P0112, P0113, and P0114 are Type B DTCs.
Diagnostic Aids
* With the ignition ON, the engine OFF, if the engine is cold, a properly functioning IAT sensor will gradually increase the scan tool IAT Sensor parameter. This is due to the heat that is generated by the MAF sensor heating elements.
* Depending on the ambient temperature, an IAT sensor signal circuit or low reference circuit that is shorted to the MAF sensor signal circuit can cause a DTC P0113 and/or P0114 to set. This condition causes a rapid fluctuation in the IAT Sensor parameter.
* An IAT sensor signal circuit that is shorted to the MAF sensor ignition circuit can cause a DTC P0113 and/or P0114 to set.
Reference Information
Schematic Reference
Engine Controls Schematics (LEA) Electrical Diagrams
Connector End View Reference
Component Connector End Views Outside Rearview Mirror - Driver
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Engine running, observe the scan tool IAT Sensor parameter. The reading should be between -39 and +149°C (-38 and +300°F) depending on the current ambient temperature and the vehicle operating conditions.
2. Operate the vehicle within the Conditions for Running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the B75C multifunction intake air sensor.
2. Ignition OFF, all vehicle systems OFF, this may take up to 2 minutes, test for less than 5 ohms between the low reference circuit terminal 7 and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
3. Ignition ON, verify the scan tool IAT Sensor parameter is colder than -39°C (-38°F).
• If warmer than the specified range, test the signal circuit terminal 8 for a short to ground. If the circuit tests normal, replace the K20 engine control module.
4. Ignition ON. Test for 4.8-5.2 V between the IAT sensor signal circuit terminal 8 and ground.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
Note: If the signal circuit is shorted to a voltage the ECM or the sensor may be damaged.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
5. If all circuits test normal, test or replace the B75C multifunction intake air sensor.
Component Testing
Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to the Temperature Versus Resistance - Intake Air Temperature Sensor (Bosch Sensor) Temperature Versus Resistance - Intake Air Temperature Sensor (Bosch Sensor) Bosch Sensor table.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Mass Airflow Sensor with Intake Air Temperature Sensor Replacement Service and Repair for multifunction intake air sensor replacement
* Control Module References Control Module References for engine control module replacement, programming, and setup