Diagnostic guide for P0113

Diagnostic Guide for P0113 - Intake Air Temperature Sensor Circuit High Input

The P0113 code indicates that the Intake Air Temperature (IAT) Sensor is reporting a high voltage signal to the Powertrain Control Module (PCM). This guide aims to help diagnose the underlying issues causing this code, ensuring proper function of the IAT sensor and related systems.

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Difficulty

Intermediate

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Estimated Time

30-60 Minutes

Estimated Diagnostic Cost

$0-$100

Typical shop charge to perform this diagnostic process. Repair parts and labor are not included.

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Tools Needed

OBDII scanner, multimeter, wiring diagram, basic hand tools

Safety Notes

Ensure the engine is off and cool before working on the intake system. Use caution when handling electrical components to avoid shorts.

Step 1

Check OBDII Code

Instruction Use an OBDII scanner to confirm the presence of the P0113 code and check for any additional codes.

Expected result P0113 code is present along with any other related codes.

If Pass Proceed to the next step to inspect the IAT sensor and wiring.

If Fail If no codes are present, further investigation may be needed to check the PCM or other related systems.

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Step 2

Inspect IAT Sensor and Wiring

Instruction Visually inspect the IAT sensor and its wiring for any signs of damage, corrosion, or loose connections.

Expected result No visible damage or corrosion on the sensor or wiring.

If Pass If the wiring and sensor appear intact, proceed to test the sensor's resistance.

If Fail If damage is found, repair or replace the affected components before retesting.

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Step 3

Test IAT Sensor Resistance

Instruction Disconnect the IAT sensor connector and use a multimeter to measure the resistance of the sensor at various temperatures (using a heat source or ice).

Expected result Resistance values should decrease as temperature increases, following the thermistor characteristics.

If Pass If the resistance values are within specifications, the sensor is likely functioning correctly. Proceed to check the signal voltage.

If Fail If resistance values are out of specification, replace the IAT sensor.

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Step 4

Check Signal Voltage at PCM

Instruction Reconnect the IAT sensor and backprobe the connector while the engine is running to measure the voltage signal sent to the PCM.

Expected result The voltage should be within the manufacturer's specified range (typically around 0.5V to 4.5V depending on temperature).

If Pass If the voltage is within range, the wiring and PCM are likely functioning correctly. Further investigation may be needed into the PCM itself.

If Fail If the voltage is too high or absent, inspect the wiring for shorts or opens, and consider testing the PCM.

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Step 5

Inspect Ground Connections

Instruction Check the ground connections for the IAT sensor and the PCM to ensure they are clean and secure.

Expected result All ground connections are tight and free of corrosion.

If Pass If the grounds are good, consider further diagnosing the PCM or related circuitry.

If Fail Clean and secure any corroded or loose ground connections, then retest the system.

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Coddy can help with this step only. Tell me what you tested or what result you got.