Diagnostic Aids

WARNING: This page is about a different car, the 2005 GMC Yukon XL, 2005 Chevrolet Suburban, and 2005 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

When the vehicle is at ambient temperature the IAT sensor and the ECT sensor temperatures should be relatively close to each other. Refer to Temperature vs Resistance .
If an intermittent condition is suspected, refer to Intermittent Conditions .

DTC P0112

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Observe the Intake Air Temperature (IAT) Sensor parameter with a scan tool. Is the IAT Sensor parameter more than the specified value?	128°C (262°F)	Go to Step 4	Go to Step 3
3	Observe the Freeze Frame/Failure Records for this DTC. 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 Fame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 4	Go to Diagnostic Aids
4	Disconnect the IAT sensor. Observe the IAT Sensor parameter with a scan tool. Is the IAT Sensor parameter less than the specified value?	-38°C (-36°F)	Go to Step 6	Go to Step 5
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 8
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 7
7	Replace the IAT sensor. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement . Did you complete the replacement?	-	Go to Step 10	-
8	Turn OFF the ignition. Disconnect the powertrain control module (PCM). Test for an intermittent and for a poor connection at the PCM. 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
9	Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. 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 - Vehicle in Vehicle DTC Information	System OK