• | 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 | P0113 | P0113* | -- |
Low Reference | -- | P0113 | P0113* | -- |
* 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: -39 to +140°C (-38 to +284°F) Varies with ambient temperature. | |||
IAT Sensor Signal | 140°C (284°F) | -40°C (-40°F) | -40°C (-40°F)* |
Low Reference | -- | -40°C (-40°F) | -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 that measures the temperature of the intake air. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and supplies a ground to the 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 |
• | The engine run time is greater than 4 minutes. |
• | Fuel cut-off is inactive |
• | The DTCs runs continuously once the above conditions are met. |
The ECM detects that the intake air temperature is greater than 133°C (272°F).
The ECM detects that the intake air temperature is less than -36°C (-34°F).
DTCs P0112 and P0113 are Type B DTCs.
DTCs P0112 and P0113 are Type B DTCs.
• | If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F). |
• | High resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit could set a DTC. |
• | Use the J 35616 Connector Test Adapter Kit for any test that requires probing the underhood fuse block terminals, component wire harness terminals, or the ECM wire harness connector terminals. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
Important: If the signal circuit of the IAT sensor is shorted to voltage the IAT sensor may be damaged.
⇒ | 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 ECM. |
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. |