P011B
DTC P011B
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P011B
- Engine Coolant Temperature (ECT) - Intake Air Temperature (IAT) Correlation
Diagnostic Fault Information
Typical Scan Tool Data
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 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:
Conditions for Running the DTC
* DTC P2610 is not set.
* The ignition has been off continuously for greater than 7 hours.
* The ignition voltage is greater than 10.5 volts.
* The engine coolant temperature is warmer than -10°C (14°F) at engine start up.
* The start up intake air temperature (IAT) sensor is warmer than -10°C (14°F).
* The engine run time is 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 (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
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool start up IAT and start up ECT parameters. The parameters should be within 10°C (50°F).
2. Engine idling for 1 minute, observe the DTC information with a scan tool. DTCs P0110, P0112 P0113, P0115, P0117, or P0118 should not set.
• If any of the DTCs are set, refer to DTC P0110, P0112, or P0113 (P0110) or DTC P0115, P0117, or P0118 (P0115).
3. 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.
Circuit/System Testing
1. Ignition ON, compare the scan tool start up IAT sensor parameter and the start up ECT sensor parameter to the ambient air temperature when the DTC set. This will aid in determining which sensor set the DTC.
2. Ignition OFF, disconnect the harness connector at the appropriate sensor.
3. Test for less than 10 ohm between the appropriate low reference circuit terminal listed below and ground G104:
* ECT sensor terminal 1
* IAT sensor terminal 2
• If greater than the specified range, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit tests normal, replace the PCM.
4. Ignition ON, verify that the sensor parameter is at -40°C (-40°F).
• If warmer than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the PCM.
5. Install a 3 A fused jumper wire between the appropriate signal circuit terminal listed below and ground. Verify the scan tool sensor parameter is greater than 139°C (280°F).
* ECT sensor terminal 2
* IAT sensor terminal 1
• If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM.
6. If all circuits test normal, test or replace the sensor.
Component Testing
1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
Note: A thermometer can be used to test the sensor off the vehicle.
2. Test the sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance (Temperature Versus Resistance) table and verify that the resistance is within 5 percent of the specification.
• If not within the specified range, replace the temperature sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Engine Coolant Temperature Sensor Replacement (Service and Repair)
* Mass Airflow Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for control module replacement, setup, and programming