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. If the ECM detects an excessively high IAT signal voltage, which is a low temperature indication, this DTC sets.
The following table illustrates the difference between temperature, resistance, and voltage:
IAT | IAT Resistance | IAT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0113 Intake Air Temperature (IAT) Sensor Circuit High Voltage
Conditions for Running the DTC
| • | The ignition is ON or the engine is operating. |
| • | This DTC runs continuously when the above condition is met. |
Conditions for Setting the DTC
The ECM detects that the IAT voltage is greater than 4.99 volts.
Action Taken When the DTC Sets - European Emissions
| • | The malfunction indicator lamp (MIL) will illuminate after 3 consecutive trips with a fail. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
| • | A history DTC is stored. |
| • | The ECM will default to 60°C (140°F) for intake air temperature. The scan tool will not show the defaulted value. |
Action Taken When the DTC Sets - Non European Emissions
| • | The malfunction indicator lamp (MIL) will illuminate. |
| • | The ECM will default to 60°C (140°F) for intake air temperature. The scan tool will not show the defaulted value. |
Conditions for Clearing the MIL/DTC - European Emissions
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Conditions for Clearing the MIL/DTC - Non European Emissions
| • | The MIL will turn OFF when the diagnostic runs and passes. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Diagnostic Aids
| • | Test the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition. |
| • | If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F). Refer to Temperature Versus Resistance . |
| • | A high resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit may not set a DTC. Refer to Circuit Testing in Wiring Systems. |
| • | For an intermittent condition, refer to Intermittent Conditions . |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |
2 |
Is the temperature at the specified value? | -40°C (-40°F) | Go to Step 4 | Go to Step 3 |
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 |
Is the voltage more than the specified value? | 5.2 V | Go to Step 5 | Go to Step 6 |
5 |
Important: The sensor may be damaged if the circuit is shorted to a voltage source. Test the signal circuit of the IAT sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
6 |
Is the IAT sensor parameter at the specified value? | 129°C (264°F) | Go to Step 10 | Go to Step 7 |
7 |
Is the IAT sensor parameter at the specified value? | 129°C (264°F) | Go to Step 9 | Go to Step 8 |
8 | Test the IAT sensor signal circuit for an open circuit or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
9 | Test the IAT sensor low reference circuit for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
10 | Test the IAT sensor signal circuit for a short to any 5-volt reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 11 |
11 | Test for shorted terminals and for poor connections at the IAT sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 |
12 | Test for shorted terminals and for poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
13 | Replace the IAT sensor. Refer to Intake Air Temperature Sensor Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
14 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
15 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 16 |
16 | Are there any DTCs that have not been diagnosed? | -- | System OK | |
