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 Descriptors
DTC P0112: Intake Air Temperature Sensor Circuit Low VoltageDTC P0113: Intake Air Temperature Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
IAT Sensor Signal | P0112 | P0113 | P0113 | P0113 | -- |
Low Reference | -- | P0113 | P0113 | P0113 | -- |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
IAT Sensor Signal | -39 to +120°C (-38 to +248°F) | 150°C (302°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -- | -40°C (-40°F) | -40°C (-40°F) |
Circuit/System Description
The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and supplies a ground to the low reference circuit.
Conditions for Running the DTC
P0112
| • | DTCs P0116, P0117, P0118, P0128, P0502 orP0503 are not set. |
| • | The engine is running for more than 10 seconds. |
| • | The engine coolant temperature (ECT) is less than 150°C (302°F). |
| • | This DTC runs continuously within the enabling conditions. |
P0113
| • | DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0128, P0502 or P0503 are not set. |
| • | The engine is running for more than 10 seconds. |
| • | The ECT is more than -40°C (-40°F). |
| • | The MAF Sensor parameter is more than 512 g/s. |
| • | This DTC runs continuously within the enabling conditions. |
Conditions for Setting the DTC
P0112
The ECM detects that the IAT is more than 149°C (300°F) for more than 5 seconds.
P0113
The ECM detects that the IAT is less than -39°C (-38°F) for more than 5 seconds.
Action Taken when the DTC Sets
DTCs P0112 or P0113 are type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0107 or P0108 are type B DTCs.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
If the ignition has been OFF for 8 hours or more the IAT and the ECT should be within 6°C (11°F) of each other and also the ambient temperature. Ignition ON, engine OFF and use a scan tool to observe the IAT and ECT parameters.
Circuit/System Testing
P0112
- Ignition ON, engine OFF.
- Disconnect the IAT sensor.
- Observe the IAT Sensor parameter with a scan tool.
| ⇒ | If the IAT Sensor parameter is less than -39°C (-38°F), then replace the IAT sensor. |
| ⇒ | If the IAT Sensor parameter is more than 149°C (300°F), then test the IAT sensor signal circuit for a short to ground. |
| ⇒ | If the IAT sensor signal circuit tests normal, replace the ECM. |
P0113
- Ignition ON, engine OFF.
- Disconnect the IAT sensor.
- Measure for the proper range of 4.9-5.2 volts between the IAT sensor signal circuit and a known ground with a DMM.
- Connect a 3A fusible link wire between the signal circuit of the IAT sensor and the low reference circuit.
- Observe the IAT sensor parameter while connecting and disconnecting a 3A fusible link wire between the IAT sensor signal and low reference circuits. This should cause the IAT Sensor parameter to toggle between the upper and lower temperature limits.
| ⇒ | If the voltage is less than 4.9 volts, test the IAT sensor signal circuit for a open/high resistance. |
Important: If a short to voltage occurs the ECT sensor may be damaged.
| ⇒ | If the voltage is more than 5.2 volts, test the IAT sensor signal circuit for a short to voltage. |
| ⇒ | If the IAT sensor signal circuit tests normal, and the voltage is still not within the proper range, then replace the control module. |
| ⇒ | If the IAT sensor parameter does not indicate more than 149°C (300°F), test the low reference circuit fora short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If the IAT sensor parameter does not toggle, replace the control module. |
| ⇒ | If the IAT sensor parameter does toggle, then test the IAT sensor signal circuit for a short to another 5 volt reference circuit. |
| ⇒ | If the IAT sensor signal circuit is not shorted to another 5-volt reference circuit, then replace the IAT sensor. |
Component Testing
Measure and record the resistance of the IAT sensor at various ambient temperatures and then compare those measurements to the Temperature Versus Resistance Table. Refer to Temperature Versus Resistance .
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Engine Control Module Replacement for engine control module replacement, setup and programming. |
