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 driveability condition.
If the vehicle has set overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F). Refer to TEMPERATURE VS RESISTANCE .
A high resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit may not set a DTC. Refer to Circuit Testing in Wiring Systems.
For an intermittent condition, refer to Intermittent Conditions .

DTC P0112

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connect End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check - Engine Controls?	-	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	Turn ON the ignition with the engine OFF. IMPORTANT: The DTCs must be cleared or a temperature of 20°C (68°F) will be displayed on the scan tool. Clear the DTCs with a scan tool. Observe the intake air temperature (IAT) sensor parameter with a scan tool. Is the temperature at the specified value?	130°C (266°F)	Go to Step 4	Go to Step 3
3	Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 4	Go to Diagnostic Aids
4	Turn OFF the ignition. Disconnect the IAT sensor. Connect a DMM between the signal circuit of the IAT sensor and a good ground. Refer to Circuit Testing in Wiring Systems. Turn ON the ignition, with the engine OFF. Is the voltage less than the specified value?	4.8 V	Go to Step 5	Go to Step 6
5	Test the signal circuit of the IAT sensor for a short to ground or a short to the IAT low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 7
6	Test for an intermittent and for a poor connection at the IAT sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 8
7	Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 9
8	Replace the IAT sensor. Refer to Intake Air Temperature (IAT) Sensor Replacement . Did you complete the replacement?	-	Go to Step 10	-
9	Replace the ECM. Refer to Engine Control Module (ECM) Replacement . Did you complete the replacement?	-	Go to Step 10	-
10	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 2	Go to Step 11
11	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List	System OK