P0112

P0112 - Intake Air Temperature Sensor 1 Circuit Low

For wiring diagrams, refer to.

• When Monitored: With the engine running and battery voltage greater than 10 volts.

• Set Condition: The PCM detects that the sensor input voltage is less than the minimum acceptable value.

Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Test Step 1 - DTC is Active

• Diagnose any CAN C communication DTCs before continuing with this test.

• Diagnose and repair any system voltage DTCs before continuing with this test.

• Start the engine and allow it to reach normal operating temperature.

When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

• With the scan tool, select view DTCs.

Is the status active for this DTC?

Yes

• Go to Test Step 2 => [ Test
Step 2 - IAT Signal Circuit Shorted to Ground ]

No

• Refer to the checking for an intermittent DTC diagnostic procedure. Refer => Non-DTC Based Diagnostics.

Test Step 2 - IAT Signal Circuit Shorted to Ground

• Turn the ignition OFF.

• Disconnect the intake air temperature sensor connector.

• Disconnect the PCM connector.

• Measure the resistance between ground and the IAT signal circuit in the harness connector.

Is the resistance more than 100 ohms?

Yes

• Go to Test Step 3 => [ Test
Step 3 - IAT Signal Circuit Shorted to Sensor Ground Circuit ]

No

• Repair the circuit for a short to ground.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 3 - IAT Signal Circuit Shorted to Sensor Ground Circuit

• Measure the resistance between the IAT signal circuit and the sensor ground circuit in the harness connector.

Is the resistance more than 100 ohms?

Yes

• Go to Test Step 4 => [ Test
Step 4 - IAT Signal Circuit Open or High Resistance ]

No

• Repair the circuit for a short to the sensor ground circuit.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 4 - IAT Signal Circuit Open or High Resistance

Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

• Measure the resistance of the sensor ground circuit between the harness connector and the appropriate terminal of special tool #8815.

Is the resistance less than 5.0 ohms?

Yes

• Go to Test Step 6 => [ Test
Step 6 - Intake Air Temperature Sensor Signal Voltage ]

No

• Repair the ground for an open or high resistance.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 6 - Intake Air Temperature Sensor Signal Voltage

• Turn the ignition OFF.

• Connect the PCM connector.

• Turn the ignition ON.

• With the scan tool, read the intake air temperature sensor signal voltage.

• The voltage should be approximately 5.0 volts with the connector disconnected.

Is the voltage as described with the connector disconnected?

Yes

• Go to Test Step 7 => [ Test
Step 7 - Intake Air Temperature Sensor ]

No

• Go to Test Step 8 => [ Test
Step 8 - PCM ]

Test Step 7 - Intake Air Temperature Sensor

• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the intake air temperature sensor and the powertrain control module.

• Look for any chafed, pierced, pinched, or partially broken wires.

• Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.

• Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.

• Look for the data to change or for the DTC to reset during the wiggle test.

• Refer to any technical service bulletins that may apply.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Replace the intake air temperature sensor.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 8 - PCM

• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the intake air temperature sensor and the powertrain control module.

• Look for any chafed, pierced, pinched, or partially broken wires.

• Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.

• Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.

• Look for the data to change or for the DTC to reset during the wiggle test.

• Refer to any technical service bulletins that may apply.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Replace the PCM.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test