• | 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. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
IAT Sensor Signal | P0112 | P0113 | P0113 | P0113 | P0111 |
Low Reference | -- | -- | P0113 | -- | -- |
Circuit | Short to Ground | Open or High Resistance | Short to Voltage |
---|---|---|---|
Operating Conditions: Ignition ON or engine running Normal IAT Parameter: Varies with ambient temperature | |||
IAT Sensor Signal | 149°C (300°F) | -40°C (-40°F) | -40°C (-40°F)* |
IAT Low Reference | -- | -40°C (-40°F)* | -- |
*Internal ECM or sensor damage may occur if the circuit is shorted to B+ |
The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal circuit, and a ground for the low reference circuit.
• | DTC P0116, P0117, P0118, P0128, P0608, or P0609 are not set. |
• | The ECT sensor is colder than 150°C (302°F). |
• | The engine run time is greater than 10 seconds. |
• | The DTC runs continuously when the above conditions are met. |
• | DTC P0101, P0102, P0103, P0116, P0117, P0118, P0128, P0608, or P0609 are not set. |
• | The ECT sensor is warmer than -40°C (-40°F). |
• | The mass air flow (MAF) sensor is less than 512 g/s. |
• | The engine run time is greater than 10 seconds. |
• | The DTC runs continuously when the above conditions are met. |
The ECM detects that the IAT sensor is warmer than 148°C (298°F) for greater than 5 seconds.
The ECM detects that the IAT sensor is colder than -39°C (-38°F) for greater than 5 seconds.
DTCs P0112 and P0113 are Type B DTCs.
DTCs P0112 and P0113 are Type B DTCs.
• | If the engine is cold, at the initial ignition ON, a properly functioning IAT sensor will indicate a gradually increasing 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 DTC P0113 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 DTC P0113 to set. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If warmer than the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the ECM. |
Important: If a short to voltage is found on the IAT signal circuit, the 3A fuse in the jumper wire will open.
⇒ | If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
Measure the resistance of the IAT sensor and compare the IAT sensor resistance to the values listed in the Temperature vs. Resistance table. Refer to Temperature Versus Resistance .
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |