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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C Sierra - 2WD 🢒 Engine 🢒 Engine Controls - 6.6L 🢒 DTC P0113

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 is contained within the mass air flow-intake air temperature (MAF/IAT) sensor assembly. The engine control module (ECM) supplies 5 volts to the IAT signal circuit. When the incoming air temperature is cold, the sensor resistance is high. When the incoming air temperature increases, the sensor resistance lowers. With higher sensor resistance, the ECM detects a higher voltage on the IAT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT signal circuit. If the ECM detects an excessively high IAT signal voltage (a low temperature indication), this diagnostic trouble code (DTC) will set.

Conditions for Running the DTC

The engine has been running for more than 8 minutes.

Conditions for Setting the DTC

The IAT sensor signal voltage indicates that the intake air temperature is less than -38°C (-36°F) for 2 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

If a short to a separate 5- volt source occurs on the IAT signal circuit this DTC may set. If this is found to be the problem, a continuity test to all other ECM circuits will be necessary to diagnose the specific circuit.

For intermittent diagnosis refer to Intermittent Conditions .

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step tests for the proper 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

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the IAT sensor temperature.

Does the scan tool indicate that the IAT sensor temperature is less than the specified value?

-38°C (-36°F)

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for running the DTC as specified in the supporting text or as close to the Freeze Frame/Failure Records data that you observed.

Does the DTC reset?

--

Go to Step 4

Go to Diagnostic Aids

4
  1. Disconnect the mass airflow-intake air temperature (MAF/IAT) sensor. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement .
  2. Connect a DMM from the IAT sensor signal circuit to a good ground.
  3. Turn ON the ignition, with the engine OFF.

Does the voltage measure above the specified value?

5 V

Go to Step 8

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor and the low reference circuit at the IAT sensor. Refer to Using Fused Jumper Wires in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the IAT sensor temperature.

Does the scan tool indicate IAT sensor temperature greater than the specified value?

148°C (298°F)

Go to Step 10

Go to Step 6

6
  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor and a known good ground.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the IAT sensor temperature.

Does the scan tool indicate IAT sensor temperature greater than the specified value?

148°C (298°F)

Go to Step 9

Go to Step 7

7
  1. Test the signal circuit of the IAT sensor for the following conditions:
    2. • A high resistance
    • An open circuit
  2. Repair the circuit as necessary. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 11

8
  1. Test the IAT sensor signal circuit for a short to voltage.
  2. Repair the circuit as necessary. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 11

9
  1. Test the IAT sensor low reference circuit for a high resistance or an open.
  2. Repair the circuit as necessary. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 11

10
  1. Inspect for poor connections at the harness connector of the IAT sensor.
  2. Repair the connections as necessary. Refer to Circuit Testing and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 12

11
  1. Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. Repair the connections as necessary. Refer to Circuit Testing and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 13

12

Replace the MAF/IAT sensor. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement .

Did you complete the replacement?

--

Go to Step 14

--

13

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 14

--

14
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 15

Go to Step 2

15

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK