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 Descriptor
DTC P011B: Engine Coolant Temperature (ECT) - Intake Air Temperature (IAT) CorrelationDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
IAT Sensor Signal | P0110, P0112 | P0110, P0113 | P0110, P0113 | P0111, P011B |
Low Reference | -- | P0110, P0113 | -- | P0111, P011B |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: -40 to +140°C (-40 to +284°F) Varies with coolant temperature. | |||
IAT Sensor Signal | 140°C (284°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F) |
Circuit Description
The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the engine coolant. The powertrain control module (PCM) supplies 5 volts to the IAT signal circuit and supplies a ground to the low reference circuit. The PCM monitors the mutual performance of the IAT and the engine coolant temperature (ECT) signals. The PCM monitors the warm up and cool down behavior of the sensors, after a vehicle driven at operating temperature is shut down. If the PCM detects that the IAT is not with in a predetermined range of ECT after a long soak, or the IAT and ECT are not within a range of each other, as compared to a previous cold start, this DTC sets.
The following table illustrates the difference between temperature, resistance, and voltage:
Temperature | ECT Resistance | ECT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
Conditions for Running the DTC
| • | DTC P2610 is not set. |
| • | The ignition has been off continuously for greater than 7 hours. |
| • | The battery voltage is greater than 10.5 volts. |
| • | The engine coolant temperature is warmer than -10°C (14°F) at engine start up. |
| • | The IAT sensor is warmer than -10°C (14°F) after engine start. |
| • | The engine has been running for greater than 15 seconds. |
| • | DTC P011B runs once per ignition cycle when the above conditions are met. |
Conditions for Setting the DTC
The difference between the ECT sensor and the IAT sensor is greater than 20°C (36°F) after engine start up.
Action Taken When the DTC Sets
DTC P011B is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P011B is a Type B DTC.
Diagnostic Aids
| • | Test the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a DTC or a driveability condition. Refer to Temperature Versus Resistance. |
| • | If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F). |
| • | High resistance in the circuit of the ECT sensor could set a DTC. |
Reference Information
Schematic Reference
Connector End View 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 idling for 1 minute, observe the DTC information with a scan tool. DTCs P0110, P0112 and P0113 should 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 DTC P0110, P0112, or P0113. |
Circuit/System Testing
- Leave the ignition OFF for greater than 7 hours.
- Ignition ON, verify that the IAT sensor parameter and the ECT sensor parameter are within 10°C (18°F) of the ambient air temperature.
- If all circuits and the sensor test normal, replace the PCM.
| ⇒ | If greater than the specified value, test the signal circuit of the appropriate sensor for high resistance. If the circuit tests normal, test the operation of appropriate temperature sensor. |
Component Testing
- Ignition OFF, disconnect the harness connector at the temperature 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 resistance 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 temperature sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for control module replacement, setup, and programming |
