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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Kodiak C-Series (Conventional) C6/C7/C8 🢒 Engine 🢒 Engine Controls - 7.8L 🢒 DTC P0112

DTC P0112 Without RPO CTF

Circuit Description

The manifold air temperature (MAT) sensor is a variable resistor, sometimes called a thermistor. The MAT sensor measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the MAT signal circuit. When the MAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance lowers. With high sensor resistance, the ECM detects a high voltage on the MAT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the MAT signal circuit. If the ECM detects an excessively low MAT signal voltage, indicating a high temperature, this DTC will set.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The MAT is more than 148°C (298°F) for more than 2 seconds.

Action Taken When the DTC Sets
    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC
    • A current DTC Last Test Failed clears when the diagnostic runs and passes.
    • Clear the DTC with a scan tool.

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

DTC P0112

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check - Engine Controls?

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Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the MAT sensor temperature with a scan tool.

Does the temperature measure more than the specified value?

128°C (262°F)

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or as close to the Freeze Frame/Failure Records data that you observed.

Does the DTC reset?

--

Go to Step 4

Go to Diagnostic Aids

4
  1. Turn OFF the ignition.
  2. Disconnect the manifold air temperature (MAT) sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the MAT sensor temperature with a scan tool.

Does the MAT sensor temperature measure less than the specified value?

-39°C (-38°F)

Go to Step 6

Go to Step 5

5

Test the signal circuit of the MAT sensor for a short to ground or a short to MAT low reference circuit and repair as necessary. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 7

6

Replace the MAT sensor.

Did you complete the replacement?

--

Go to Step 9

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7
  1. Turn OFF the ignition.
  2. Disconnect the engine control module (ECM). Refer to Engine Control Module Replacement/Restore Fuel Rate Data .
  3. Inspect for poor connection at the ECM harness connector. 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 9

Go to Step 8

8

Replace the ECM. Refer to Engine Control Module Replacement/Restore Fuel Rate Data .

Did you complete the replacement?

--

Go to Step 9

--

9
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 10

Go to Step 2

10

Observe the stored information, Capture Info with a scan tool.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK