PRE-RELEASE
DTC P0112 or P0113
| DTC P0112 or P0113 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptors |
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 intake 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 intake air. The engine control module (ECM) supplies 5 V 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 |
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Cold
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High
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High
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Warm
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Low
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Low
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| Conditions for Running the DTC |
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The ignition is ON or the engine is running.
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The ignition voltage is greater than 8.5 V.
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The DTCs run continuously when the above conditions are met.
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| Conditions for Setting the DTC |
P0112
The ECM detects that an IAT 1 circuit is shorted to ground.P0113
The ECM detects that an IAT 1 circuit is open or shorted to voltage.| Action Taken When the DTC Sets |
DTCs P0112 and P0113 are Type B DTCs.
| Conditions for Clearing the DTC |
DTCs P0112 and P0113 are Type B DTCs.
| Diagnostic Aids |
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If the engine has sat overnight, the IAT sensor and the engine coolant temperature (ECT) sensor values should display within 3°C (5°F).
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High resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit may set a DTC.
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| Reference Information |
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
| Circuit/System Verification |
| 1. |
Ignition ON, check the diagnostic trouble code (DTC) information with a scan tool. DTC P0112 or P0113 are not set.
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| 2. |
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.
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| Circuit/System Testing |
| 1. |
Ignition OFF disconnect the harness connector at the B75 Mass Air Flow Sensor.
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| 2. |
Test for less than 5 Ω between the low reference circuit terminal 1 and ground.
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| 3. |
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.
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Ignition ON, test for 4.8-5.2 V between the IAT signal circuit terminal 3 and ground.
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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.
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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.
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| 7. |
If all circuits test normal, test or replace the B75 Mass Air Flow Sensor.
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| Component Testing |
Static Test
Test the resistance between the signal circuit terminal 3 and the low reference circuit terminal 1 at various ambient temperatures. Note the measured values. Compare those measurements to the Temperature Versus Resistance (ECT and IAT Sensor) Temperature Versus Resistance (Exhaust Temperature Sensor)| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Mass Airflow Sensor with Intake Air Temperature Sensor Replacement
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Control Module References
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