DTC P0111-P0113 — LNP or LNQ
Diagnostic Instructions
DTC Descriptors
DTC P0111 00: Intake Air Temperature (IAT) Sensor 1 Performance
DTC P0112 00: Intake Air Temperature (IAT) Sensor 1 Circuit Low Voltage
DTC P0113 00: Intake Air Temperature (IAT) Sensor 1 Circuit High Voltage
Circuit/System Description
The inlet air temperature (IAT) sensor 1 is an integral part of the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the inlet air. The engine control module (ECM) supplies 5 V to the IAT signal circuit and supplies a ground to the 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
| • | The ignition is ON or the engine is running. |
| • | The ignition voltage is greater than 8.5 V. |
| • | The DTCs run continuously once the above conditions are met. |
Conditions for Setting the DTC
P0111 00
The ECM detects that the IAT 1 deviates less than 1.5°C (35°F) since engine start.
P0112 00
The ECM detects that an IAT 1 circuit is shorted to ground.
P0113 00
The ECM detects that an IAT 1 circuit is open or shorted to voltage.
Action Taken When the DTC Sets
DTCs P0111 00, P0112 00 and P0113 00 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0111 00, P0112 00 and P0113 00 are Type B DTCs.
Diagnostic Aids
| • | If the engine has sat overnight, the IAT sensor and the engine coolant temperature (ECT) sensor values should display within 3°C (5°F). |
| • | High resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit may set a DTC. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
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
- Ignition ON, observe the DTC information with a scan tool. DTC P0111 00, P0112 00 or P0113 00 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.
Circuit/System Testing
- Ignition OFF disconnect the harness connector at the B75B Mass Air Flow/Intake Air Temperature Sensor.
- Test for less than 5 Ω between the low reference circuits and ground listed below:
| ⇒ | 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 K20 Engine Control Module. |
- Ignition ON, test for 4.8-5.2 V between the IAT signal circuits and ground listed below:
| ⇒ | If less than the specified range, test the signal circuit for an open or a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
- If all circuits test normal, test or replace the B75B Mass Air Flow/Inlet Air Temperature Sensor.
Component Testing
Static Test
Test and record the resistance between the signal circuit terminals and the low reference circuit terminals listed below at various ambient temperatures. Compare those measurements to the
Temperature Versus Resistance : ECT and IAT Sensor table and verify that the resistance is within 5% of the specification.
| • | Signal circuit terminal 3 and low reference circuit terminal 1 with LNP |
| • | Signal circuit terminal A and low reference circuit terminal B with LNQ |
| ⇒ | If not within the specified range, replace the B75B Mass Air Flow/Intake Air Temperature Sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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