Hummer H2. Manual — part 1524

DTC P0112

Circuit Description

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low
reference circuit. The IAT sensor measures the temperature of the air entering the engine. The powertrain
control module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit.
When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor
resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit.
With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an
excessively low IAT signal voltage, indicating a high temperature, DTC P0112 sets.

Conditions for Running the DTC

z

DTCs P0502, P0503 are not set.

z

The engine run time is more than 45 seconds.

11

Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.
Did you find and correct the condition?

-

Go to Step 15

Go to Step 12

12

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 15

Go to Step 14

13

Replace the MAP sensor. Refer to Manifold
Absolute Pressure (MAP) Sensor Replacement .
Did you complete the replacement?

-

Go to Step 15

-

14

Replace the PCM. Refer to Powertrain Control
Module (PCM) Replacement .
Did you complete the replacement?

-

Go to Step 15

-

15

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. 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 16

16

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

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0068 To DTC P0141/P0161) - 4.8L, 5.3L, and 6.0L -

Hummer H2

z

The vehicle speed sensor (VSS) indicates that the vehicle speed is more than 40 km/h (25 mph).

Conditions for Setting the DTC

The PCM detects that the IAT Sensor parameter is more than 128°C (262°F) for 5 seconds.

Action Taken When the DTC Sets

z

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition
cycle that the diagnostic runs and fails.

z

The control module records the operating conditions at the time the diagnostic fails. The first time the
diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic
reports a failure on the second consecutive ignition cycle, the control module records the operating
conditions at the time of the failure. The control module writes the operating conditions to the Freeze
Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

z

The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles
that the diagnostic runs and does not fail.

z

A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

z

A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other
emission related diagnostic.

z

Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

z

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 .

z

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-
Engine Controls?

-

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls

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

1. Observe the Freeze Frame/Failure Records

for this DTC.

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0068 To DTC P0141/P0161) - 4.8L, 5.3L, and 6.0L -

Hummer H2

3

2. Turn OFF the ignition for 30 seconds.

3. Start the engine.

4. 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

1. Disconnect the IAT sensor.

2. 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

1. Turn OFF the ignition.

2. Disconnect the powertrain control module

(PCM).

3. 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 Powertrain Control
Module (PCM) Replacement .
Did you complete the replacement?

-

Go to Step 10

-

1. Clear the DTCs with a scan tool.

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0068 To DTC P0141/P0161) - 4.8L, 5.3L, and 6.0L -

Hummer H2

DTC P0113

Circuit Description

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low
reference circuit. The IAT sensor measures the temperature of the air entering the engine. The powertrain
control module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit.
When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor
resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit.
With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an
excessively high IAT signal voltage, indicating a low temperature, DTC P0113 sets.

Conditions for Running the DTC

z

DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0125, P0128, P0502, P0503 are not set.

z

The engine run time is more than 120 seconds.

z

The vehicle speed sensor (VSS) indicates that the vehicle speed is less than 11 km/h (7 mph).

z

The engine coolant temperature (ECT) is more than 60°C (140°F).

z

The mass air flow (MAF) is less than 15 g/s.

Conditions for Setting the DTC

The PCM detects that the IAT Sensor parameter is less than -38°C (-36°F) for more than 5 seconds.

Action Taken When the DTC Sets

z

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition
cycle that the diagnostic runs and fails.

z

The control module records the operating conditions at the time the diagnostic fails. The first time the
diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic
reports a failure on the second consecutive ignition cycle, the control module records the operating
conditions at the time of the failure. The control module writes the operating conditions to the Freeze

10

2. Turn OFF the ignition for 30 seconds.

3. Start the engine.

4. 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

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0068 To DTC P0141/P0161) - 4.8L, 5.3L, and 6.0L -

Hummer H2