| Table 1: | DTC P0113 |
Circuit Description
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 powertrain control module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an excessively high IAT signal voltage, indicating a low temperature, DTC P0113 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 Descriptors
This diagnostic procedure supports the following DTC.
DTC P0113 IAT Sensor Circuit High Voltage
Conditions for Running the DTC
| • | DTCs P0101, P0102, P0103, P0117, P0118, are not set. |
| • | The engine is operating for more than 100 seconds. |
| • | The vehicle speed is less than 11 km/h (7 mph). |
| • | The engine coolant temperature is more than 0°C (32°F). |
Conditions for Setting the DTC
| • | The IAT is less than -35°C (-31°F). |
| • | The condition exists for more than 19 seconds. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | Use the Temperature vs Resistance table in order to test the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in a driveability condition. If the engine has sat overnight, the engine coolant temperature and the intake air temperature values should display within a few degrees. If the temperatures are not within 3°C (5°F), refer to Temperature Versus Resistance . |
| • | If a short to a separate 5-volt source occurs this DTC may set. If this condition exists, a continuity test to all other PCM 5-volt reference circuits will be necessary. |
| • | If an intermittent condition is suspected, refer to Intermittent Conditions . |
Test Description
The number below refer to the step number on the diagnostic table.
-
This step isolates the condition. If the temperature changes, test for a condition in the low reference circuit. If the temperature remains the same test the signal circuit for a condition.
-
This step tests for the correct operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain 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 |
Important: If you were instructed to this DTC from DTC P0116 proceed to step 4.
Is the temperature more than the specified value? | -38°C (-36°F) | Go to Step 3 | Go to Step 4 |
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 |
Is the temperature less than the specified value? | 139°C (282°F) | Go to Step 5 | Go to Step 6 |
Is the temperature more than the specified value? | 139°C (282°F) | Go to Step 7 | Go to Step 8 | |
Important: If the fuse in the jumper wire opens, repair the short to B+, and replace the sensor. Refer to Intake Air Temperature Sensor Replacement . Did any additional DTCs set? | -- | Go to Step 11 | Go to Step 9 | |
7 | Test the low reference circuit of the IAT sensor for an open, or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 |
8 | Test the signal circuit of the IAT sensor for an open, or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 |
9 | Test for shorted terminals and for poor connections at the IAT sensor. 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 14 | Go to Step 12 |
10 | Test for shorted terminals and for poor connections at the PCM. 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 14 | Go to Step 13 |
11 | Repair the short between the signal circuit of the IAT sensor and the circuit for which the DTC set. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 14 | -- |
12 | Replace the IAT sensor. Refer to Intake Air Temperature Sensor Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
13 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
14 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 15 |
15 | Observe the Capture Info with a scan tool. Are there any DTCs that you have not diagnosed? | -- | System OK | |
