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 provide 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 | P0113¹ | P0110, P0111 |
Low Reference | -- | P0113 | P0113¹ | P0110, P0111 |
¹ 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)¹ |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)¹ |
¹ 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 operating 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 operating 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). |
| • | The use of the engine block heater may cause DTC P0111 to set. Verify with the customer whether the block heater was in use prior to the DTC setting. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Circuit/System Verification
- Verify that the following DTCs are not set: P0112, P0113, P0115, P0117, P0118, P0125, P0128.
- Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. DTC P0110 or P0111 should not set.
- If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.
| ⇒ | If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle . |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector of the IAT sensor.
- Ignition ON, clear the DTC information with a scan tool.
- Ignition ON, verify that the scan too IAT sensor parameter is at -40°C (-40°F).
- Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit and ground.
- Ignition ON, clear the DTC information with a scan tool.
- Connect a 1A fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool IAT sensor parameter is greater than 128°C (262°F).
- If all circuits/connections test normal, test or replace the IAT sensor.
| ⇒ | If greater than the specified value, test the signal circuit for a short to ground. If the circuit/connections test normal, replace the ECM. |
| ⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit/connections test 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 value, test the signal circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM. |
Component Testing
- Ignition OFF, disconnect the harness connector of 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 the resistance vs. temperature is not within 5 percent, 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 |
