Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0112: Intake Air Temperature (IAT) Sensor Circuit Low VoltageDTC P0113: Intake Air Temperature (IAT) Sensor Circuit High Voltage
DTC P0114: Intake Air Temperature (IAT) Sensor Circuit Intermittent
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
IAT Sensor Signal | P0112, P0114 | P0113, P0114 | P0113, P0114 | P0113, P0114 | P0114, P2199 |
Low Reference | -- | P0113, P0114 | P0113, P0114 | P0113, P0114 | P0114, P2199 |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine Running Parameter Normal Range: Varies with ambient temperature | |||
IAT Sensor Signal | 143°C (289°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F) |
Circuit/System Description
The intake air temperature (IAT) sensor is integrated with the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the air when it first enters the induction system. The engine control module (ECM) supplies 5V to the IAT signal circuit and a ground for the IAT low reference circuit.
Conditions for Running the DTC
P0112
| • | The ignition is ON or the engine is running. |
| • | This DTC runs continuously within the enabling conditions. |
P0113
| • | The engine is running. |
| • | This DTC runs continuously within the enabling conditions. |
P0114
| • | The ignition is ON or the engine is running. |
| • | This DTC runs continuously within the enabling conditions. |
Conditions for Setting the DTC
P0112
The ECM detects that the IAT is warmer than 142°C (288°F) for greater than 15 seconds.
P0113
The ECM detects that the IAT is colder than -39°C (-38°F) for greater than 15 seconds at idle.
P0114
The ECM detects that the IAT sensor signal is intermittent or has abruptly changed for greater than 4 seconds.
Action Taken When the DTC Sets
DTCs P0112, P0113, P0114 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0112, P0113, P0114 are Type B DTCs.
Diagnostic Aids
| • | When the engine is cold, at ignition ON, 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 that is shorted to the MAF sensor signal circuit can cause a DTC P0113 and/or a DTC P0114 to set. This condition may cause either a rapid fluctuation in the IAT Sensor parameter or cause it to become stuck at a given value. |
| • | An IAT low reference circuit that is open can cause the IAT Sensor parameter response to be sluggish. |
| • | A MAF sensor ground circuit that is open will cause a DTC P0113 and/or a DTC P0114 to set. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
| • | If the ignition has been OFF for 8 hours or greater, the IAT, the IAT 2 and the engine coolant temperature (ECT) should be within 9°C (16°F) of each other. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2 and the ECT Sensor parameters. Compare those sensor parameters to each other to determine if the condition is current. |
| • | Engine running, observe the scan tool IAT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions. |
| • | Operate the vehicle within the Conditions for Running the DTC to verify 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
- Ignition OFF, disconnect the harness connector at the B75B MAF/IAT sensor.
- Ignition OFF, test for less than 5Ω between the MAF sensor ground circuit terminal B and ground.
- Ignition OFF, test for less than 5Ω between the IAT low reference circuit terminal D and ground.
- Ignition ON, verify the scan tool IAT Sensor parameter is colder than -39°C (-38°F).
- Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool IAT Sensor parameter is warmer than 142°C (288°F).
- If the circuits test normal, test or replace the MAF sensor.
| ⇒ | If greater than the specified range, test the MAF sensor ground circuit for an open/high resistance. |
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM. |
| ⇒ | If warmer than the specified range, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the K20 ECM. |
| ⇒ | If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal replace the K20 ECM. |
Component Testing
Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to the Temperature Versus Resistance table.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
