Hummer H2. Manual — part 1623

Is the voltage more than the specified value?

Go to Step 7

Go to Step 8

7

1. Connect a 3-amp fused jumper wire between

the 5-volt reference circuit of the MAP sensor
and the signal circuit of the MAP sensor.

2. Observe the MAP sensor parameter with the

scan tool.

Is the voltage more than the specified value?

4.9 V

Go to Step 11

Go to Step 9

8

Test the 5-volt reference circuit between the
powertrain control module (PCM) and the MAP
sensor for an open. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 13

Go to Step 10

9

Test the MAP sensor signal circuit between the PCM
and the MAP sensor for a short to ground or an open.
Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.
Did you find and correct the condition?

-

Go to Step 13

Go to Step 10

10

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 13

Go to Step 12

11

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

-

Go to Step 13

-

12

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

-

Go to Step 13

-

13

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 14

14

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

DTC P0108

Circuit Description

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The
pressure changes occur based on the engine load. The MAP sensor has the following circuits:

z

5-volt reference circuit

z

Low reference circuit

z

MAP sensor signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The
PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the
MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a
low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM should detect a high signal
voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The
MAP sensor is also used in order to determine the barometric pressure (BARO). This occurs when the ignition
switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is
operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range.

If the PCM detects a MAP sensor signal voltage that is excessively high, DTC P0108 sets.

Conditions for Running the DTC

z

DTCs P0068, P0120, P0220, P1125, P1516, P2101, P2108, P2120, P2121, P2125, P2135 are not set.

z

The engine is running.

z

The throttle angle is less than 1 percent when the engine speed is less than 1,200 RPM.

OR

z

The throttle angle is more than 20 percent when the engine speed is more than 1,200 RPM.

Conditions for Setting the DTC

The PCM detects that the MAP sensor voltage is more than 4.9 volts for more than 4 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.

2004 Hummer H2

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

Hummer H2

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.

DTC P0108

Step

Action

Values

Yes

No

Schematic Reference:Engine Controls Schematics
Connector End View Reference:Engine Controls Connector End Views or Powertrain Control
Module (PCM) 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

1. Start the engine.

2. Observe the MAP sensor parameter with the

scan tool.

Is the voltage more than the specified value?

4.9 V

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. 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 Intermittent

Conditions

4

Inspect the manifold absolute pressure (MAP) sensor
vacuum source for the following conditions:

z

A leak

z

A restriction

z

A faulty connection

Did you find and correct the condition?

-

Go to Step 15

Go to Step 5

Monitor the DTC Information with the 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

5

Is DTC P0641 also set?

-

Go to Step 9

Go to Step 6

6

Test for an intermittent and for a poor connection at
the MAP 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 15

Go to Step 7

7

1. Turn OFF the ignition.

2. Disconnect the MAP sensor electrical

connector.

3. Turn ON the ignition, with the engine OFF.

4. Observe the MAP sensor parameter with the

scan tool.

Is the voltage less than the specified value?

0.1 V

Go to Step 8

Go to Step 10

8

1. Turn OFF the ignition.

2. Connect a jumper wire between each of the

terminals in the MAP sensor harness
connector and the corresponding terminal at
the MAP sensor. Refer to Using Connector
Test Adapters in Wiring Systems.

3. Turn ON the ignition, with the engine OFF.

4. Measure the voltage from the low reference

circuit of the MAP sensor at the jumper wire
terminal to a good ground with the DMM.
Refer to Measuring Voltage Drop in Wiring
Systems.

Is the voltage more than the specified value?

0.2 V

Go to Step 11

Go to Step 13

9

1. Turn OFF the ignition.

2. Disconnect the MAP sensor electrical

connector.

3. Turn ON the ignition, with the engine OFF.

4. Observe the MAP sensor parameter with the

scan tool.

Is the voltage less than the specified value?

0.1 V

Go to DTC

P0641

Go to Step 10

10

Test the MAP sensor signal circuit between the
powertrain control module (PCM) and the MAP
sensor for a short to voltage. Refer to Circuit
Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 15

Go to Step 14

Test the low reference circuit between the PCM and
the MAP sensor for an open or for high resistance.

2004 Hummer H2

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

Hummer H2