P0112

DTC P0112

DTC DESCRIPTORS

DTC P0112
Intake Air Temperature (IAT) Sensor Circuit Low Voltage

DTC P0113
Intake Air Temperature (IAT) Sensor Circuit High Voltage

DIAGNOSTIC FAULT INFORMATION




Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

TYPICAL SCAN TOOL DATA

IAT Sensor:

CIRCUIT DESCRIPTION
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 table illustrates the difference between temperature, resistance, and voltage:

CONDITIONS FOR RUNNING THE DTC

P0112
- DTC P0501 is not set.
- The engine run time is more than 120 seconds or the ignition has been off for more than 300 minutes before vehicle is started.
- The vehicle speed is greater than 50 km/h (31 mph).
- This DTC runs continuously once the above conditions are met.

P0113
- DTC P0501 is not set.
- The engine airflow is less than 15 g/s.
- The vehicle speed is less than 25 km/h (15 mph).
- The engine coolant temperature (ECT) sensor test is ran under two different conditions with the following conditions present:

Condition 1
- The engine run time is more than 120 seconds.
- The ECT sensor is greater than 70°C (158°F).

Condition 2
- The ignition has been off for more than 300 minutes before vehicle is started.
- The ECT sensor is greater than 60°C (140°F).

- This DTC runs continuously once the above conditions are met.

CONDITIONS FOR SETTING THE DTC

P0112
The ECM detects that the IAT sensor is more than 149°C (300°F) for more than 10 seconds.

P0113
The ECM detects that the IAT sensor parameter is less than -38°C (-36°F) for more than 4 seconds.

ACTION TAKEN WHEN THE DTC SETS
DTC P0112 and P0113 are Type B DTCs.

CONDITIONS FOR CLEARING THE MIL/DTC
DTC P0112 and P0113 are Type B DTCs.

DIAGNOSTIC AIDS
- If the vehicle has set 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 may not set a DTC.

CIRCUIT/SYSTEM VERIFICATION
1. With the engine idling for 4 minutes, observe the DTC information with a scan tool. DTC P0112 or P0113 should not set.
2. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the harness connector of the IAT sensor.
2. Ignition ON, verify that the IAT sensor parameter is at -40°C (-40°F).

IMPORTANT: The DTCs must be cleared or a temperature of 20°C (68°F) will be displayed on the scan tool.

- If greater than -40°C (-40°F), test the signal circuit of the IAT sensor for a short to ground. If the circuit/connections test normal, replace the ECM.

3. Test for less than 0.5 volt between the low reference circuit of the IAT sensor and the negative terminal of the battery.
- If greater than 0.5 volt, test the low reference circuit of the IAT sensor for a short to voltage. If the circuit/connections test normal, replace the ECM.
4. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit of the IAT sensor and the negative terminal of the battery.
- If greater than 5 ohms, test the low reference circuit of the IAT sensor for an open/high resistance. If the circuit/connections test normal, replace the ECM.
5. Install a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the IAT sensor and verify the IAT sensor parameter is greater than 128°C (262°F).

IMPORTANT: The DTCs must be cleared or a temperature of 20°C (68°F) will be displayed on the scan tool.

- If less than 128°C (262°F), test the signal circuit of the IAT sensor for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.

6. If all circuits/connections test normal, test or replace the IAT sensor.

COMPONENT TESTING
1. Ignition OFF, disconnect the harness connector of the IAT sensor.
2. Test the IAT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature vs Resistance table and verify that the resistance is within 5 percent of the specification.

IMPORTANT: A thermometer can be used to test the sensor off the vehicle.
- If the resistance vs. temperature is not within 5 percent, replace the IAT sensor.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests