Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0110: Intake Air Temperature (IAT) Sensor CircuitDTC P0111: Intake Air Temperature (IAT) Sensor Performance
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
IAT Sensor Signal | P0112 | P0113 | P0113* | P0110, P0111 |
Low Reference | -- | P0113 | P0113* | P0110, P0111 |
* Internal ECM or sensor damage may occur if the circuit is shorted to B+. | ||||
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: Varies with ambient temperature | |||
IAT Sensor Signal | 141°C (286°F) | -40°C (-40°F) | -40°C (-40°F)* |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)* |
* Internal ECM or sensor damage may occur if the circuit is shorted to B+. | |||
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.
The following table illustrates the difference between temperature, resistance, and voltage:
IAT | IAT Resistance | IAT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
Conditions for Running the DTC
| • | DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0502, P0562, P0563, and P2610 are not set. |
| • | The ignition is OFF for greater than 8 hours. |
| • | The engine is running. |
P0110-Idle Test
| - | The vehicle speed is less than 2 km/h (1.2 mph). |
| - | The throttle position (TP) sensor is less than 2 percent. |
| - | The engine is running at idle. |
| - | The above conditions are met for more than 60 seconds. |
P0110-Cruise Test
| - | The vehicle speed is more than 40 km/h (25 mph). |
| - | The mass air flow (MAF) sensor is more than 15 g/s. |
| - | The engine is running at a cruise. |
| - | The above conditions are met for more than 300 seconds. |
P0111-Skew High Test
| - | The calculated engine airflow is greater than 15 g/s. |
| - | The vehicle speed is greater than 40 km/h (25 mph). |
P0111-Skew Low Test
| - | The calculated engine airflow is greater than 15 g/s. |
| - | The vehicle speed is greater than 40 km/h (25 mph). |
| - | The start-up engine coolant temperature (ECT) minus the start-up intake air temperature (IAT) is greater than 20°C (36°F). |
| - | The start-up ECT is greater than -20°C (-4°F). |
| • | The DTCs run once an ignition cycle once the above conditions are met. |
Conditions for Setting the DTC
P0110
| • | Cruise Test--The ECM does not detect an IAT change of greater than 3°C (5°F). |
| • | Startup Test--The ECM does not detect a difference of 3°C (5°F) between the previous ignition cycle IAT and the start-up IAT of the next ignition cycle. |
P0111
| • | Skew High Test--The ECM detects a 20°C (36°F) difference between the start-up IAT and the start-up ECT. |
| • | Skew Low Test--The ECM detects a 20°C (36°F) difference between the start-up ECT and the start-up IAT. |
Action Taken When the DTC Sets
DTC P0110 and P0111 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTC P0110 and P0111 are Type B DTCs.
Diagnostic Aids
If the vehicle has set overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).
Reference Information
Schematic Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine running, observe the DTC information with a scan tool. Verify that DTC P0112, P0113, P0115, P0117, P0118, P0125, P0128 is not set.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
| ⇒ | If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle. |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the IAT sensor.
- Ignition ON, clear the DTC information with a scan tool.
- Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal 2 and ground.
- Ignition ON, verify the scan tool IAT sensor parameter is at -40°C (-40°F).
- Ignition ON, clear the DTC information with a scan tool.
- Connect a 1A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool IAT sensor parameter is greater than 128°C (262°F).
- If all circuits test normal, test or replace the IAT sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
Important: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
| ⇒ | If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
Component Testing
- Ignition OFF, disconnect the harness connector at the IAT sensor.
- Test the IAT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance table and verify that the temperature is within 5 percent of the specification.
Important: A thermometer can be used to test the sensor off the vehicle.
| ⇒ | If not within the specified range, replace the IAT sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
