DTC P0112 or P0113 (LLU)
| DTC P0112 or P0113 (LLU) |
| 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 Circuit Low Voltage
DTC P0113 00
Intake Air Temperature (IAT) Sensor Circuit High Voltage
| Diagnostic Fault Information |
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
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Sensor Signal
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P0112 00
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P0113 00
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P0113 00
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-
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Ground
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-
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P0113 00
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P0113 00
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-
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| Typical Scan Tool Data |
IAT Sensor
| Circuit | Short to Ground | Open | Short to Voltage |
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Operating Conditions:
Engine running
Parameter Normal Range: Varies with ambient temperature |
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Sensor Signal
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150°C (302°F)
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-40°C (-40°F)*
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-40°C (-40°F)
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Ground
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-
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-40°C (-40°F)*
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-40°C (-40°F)
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* Internal ECM or sensor damage may occur if the circuit is shorted to B+.
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| Circuit/System Description |
The intake air temperature (IAT) sensor is an integral part of the mass air flow (MAF) sensor. 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 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 |
P0112 00
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DTCs P0117 00, or P0118 00, are not set.
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The ignition is ON.
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This DTC runs continuously within the enabling conditions.
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P0113 00
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DTCs P0117 00, or P0118 00, are not set.
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The engine run time is greater than 10 s.
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This DTC runs continuously once the above conditions are met.
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| Conditions for Setting the DTC |
P0112 00
The ECM detects that the IAT sensor is greater than 138°C (280°F) for greater than 2 s.P0113 00
The ECM detects that the IAT sensor parameter is colder than -44°C (-47°F) for greater than 2 s.| Action Taken When the DTC Sets |
DTC P0112 00, and P0113 00 are Type B DTCs.
| Conditions for Clearing the DTC |
DTC P0112 00, and P0113 00 are Type B DTCs.
| Diagnostic Aids |
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When the engine is cold, at ignition ON, a properly functioning IAT sensor will gradually increase the scan tool IAT Sensor parameter. This is due to the heat that is generated by the MAF sensor heating elements.
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Depending on the ambient temperature, an IAT sensor signal circuit that is shorted to the MAF sensor signal circuit can cause a DTC P0113 00 to set. This condition may cause either a rapid fluctuation in the IAT Sensor parameter or cause it to become stuck at a given value.
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An IAT low reference circuit that is open can cause the IAT Sensor parameter response to be sluggish.
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A MAF sensor ground circuit that is open will cause a DTC P0113 00 to set.
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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 for scan tool information
| Circuit/System Verification |
| 1. |
If the ignition has been OFF for 8 h or greater, the B75B Mass Air Flow/Intake Air Temperature Sensor (IAT 1), the B111 Turbocharger Boost Sensor (IAT 2) and the B34A Engine Coolant Temperature Sensor 1 should be within 9°C (16°F) of each other. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2 and the ECT Sensor parameters. Compare those sensor parameters to each other to determine if the condition is current.
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| 2. |
Engine running, observe the scan tool IAT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions.
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| 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.
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| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect the harness connector at the B75B Mass Air Flow/Intake Air Temperature Sensor.
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| 2. |
Ignition OFF for 90 s, test for less than 5 Ω between the ground circuit terminal 2 and ground.
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| 3. |
If greater than the specified range, test the ground circuit for an open/high resistance.
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| 4. |
Ignition OFF, test for less than 5 Ω between the B75B Mass Air Flow/Intake Air Temperature Sensor (IAT 1) low reference circuit terminal 3 and ground.
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| 5. |
If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
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| 6. |
Ignition ON, verify the scan tool IAT Sensor parameter is colder than -39°C (-38°F).
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| 7. |
If greater than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 engine control module.
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| 8. |
Install a 3 A fused jumper wire between the B75B Mass Air Flow/Intake Air Temperature Sensor signal circuit terminal 1 and ground. Verify the scan tool IAT Sensor parameter is warmer than 142°C (288°F).
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| 9. |
If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal replace the K20 Engine Control Module.
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| 10. |
If all circuits/connections test normal, replace the B75B Mass Air Flow/Intake Air Temperature Sensor.
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| Component Testing |
Static Test
Measure and record the resistance of the B75B Mass Air Flow/Intake Air Temperature Sensor (IAT 1) at various ambient temperatures, then compare those measurements to the Temperature Versus Resistance table.| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Mass Airflow Sensor Replacement (LLU/A16LET)
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Control Module References
for ECM replacement, setup, and programming
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