• | 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 | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
IAT Sensor Signal | P0112, P1112 | P0113, P1111 | P0113, P1111* | P0110, P0111 |
Low Reference | -- | P0113, P1111 | P0113, P1111* | P0110, P0111 |
* Internal ECM or sensor damage may occur if the circuit is shorted to B+. |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: Varies with ambient temperature | |||
IAT Sensor Signal | 130°C (266°F) | 20°C (68°F) | 20°C (68°F)* |
Low Reference | -- | 20°C (68°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 that measures the temperature of the air entering the engine. The IAT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit.
The following table illustrates the difference between temperature, resistance, and voltage:
IAT | IAT Resistance | IAT Signal Voltage |
---|---|---|
Cold | High | High |
Warm | Low | Low |
• | DTCs P0117, P0118, and P0502 are not set. |
• | The engine run time is greater than 120 seconds. |
• | The engine airflow is less than 15 g/s. |
• | The engine coolant temperature (ECT) sensor is greater than 70°C (158°F). |
• | The vehicle speed is less than 25 km/h (15 mph). |
• | This DTC runs continuously once the above conditions are met. |
• | DTC P0502 is not set. |
• | The engine run time is greater than 120 seconds. |
• | The vehicle speed is greater than 50 km/h (31 mph). |
• | This DTC runs continuously once the above conditions are met. |
The ECM detects that the IAT sensor parameter is less than -38°C (-36°F) for greater than 3 seconds intermittently.
The ECM detects that the IAT sensor is greater than 149°C (300°F) for greater than 20 seconds intermittently.
DTCs P1111 and P1112 are Type C DTCs.
DTCs P1111 and P1112 are Type C DTCs.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle. |
Engine running, observe the scan tool intake air temperature (IAT) sensor parameter while moving the related wiring harness and harness connectors. The reading should not change abruptly.
⇒ | If the reading changes abruptly, repair the wiring harness and harness connectors. |
Important: A thermometer can be used to test the sensor off the vehicle.
⇒ | If not within the specified range, replace the IAT sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for engine control module replacement, setup, and programming |