Hummer H2. Manual — part 1620

DTC P0103

Circuit Description

The mass air flow (MAF) sensor is an airflow meter that measures the amount of air entering the engine. The
powertrain control module (PCM) uses the MAF sensor signal to provide the correct fuel delivery for all engine
speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large
quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the
following circuits:

z

An ignition 1 voltage circuit

z

A ground circuit

z

A signal circuit

Did you complete the repair?

Go to Step 28

-

24

Repair the short between the MAF sensor signal
circuit and the 5-volt reference circuit for which the
DTC set. Refer to Wiring Repairs in Wiring
Systems.
Did you complete the repair?

-

Go to Step 28

-

25

Repair the circuits that are shorted together. Refer to
Wiring Repairs in Wiring Systems.
Did you complete the repair?

-

Go to Step 28

-

26

Replace the MAF/IAT sensor. Refer to Mass Air
Flow (MAF)/Intake Air Temperature (IAT)
Sensor Replacement .
Did you complete the replacement?

-

Go to Step 28

-

27

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

-

Go to Step 28

-

28

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 29

29

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

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a
frequency based on the inlet airflow through the sensor bore. The frequency varies within a range of near 2,000
Hertz at idle to near 10,000 Hertz at maximum engine load. If the PCM detects the frequency signal is more
than the possible range of a correctly operating MAF sensor DTC P0103 sets.

Conditions for Running the DTC

z

The engine is running for more than 2 seconds.

z

The Engine Speed parameter is more than 400 RPM.

z

The Ignition 1 Signal parameter is more than 8 volts.

z

The MAF Sensor parameter is stable for more than 1 second.

Conditions for Setting the DTC

The PCM detects that the MAF sensor frequency signal is more than 13,500 Hertz for more than 1.2 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

Inspect the air induction system for any water intrusion. The water rapidly cools the hot sensing elements
in the sensor causing a false indication of excessive airflow. Any water that reaches the MAF sensor will
skew the sensor and may cause this DTC to set.

z

A poor connection in the ignition 1 voltage circuit of the MAF sensor may cause this DTC to set.

If the condition is intermittent, refer to Intermittent Conditions .

Test Description

2004 Hummer H2

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

Hummer H2

The numbers below refer to the step numbers on the diagnostic table.

3: This step tests for electromagnetic interference (EMI) on the signal circuit of the MAF sensor. A
frequency reading with the MAF sensor disconnected indicates an EMI related fault or a poor connection
at the PCM. Disconnecting the MAF sensor may set additional related DTCs.

4: This step will determine if incorrect harness routing has caused this DTC to set.

5: This step will determine if water intrusion has caused this DTC to set.

DTC P0103

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. Observe the Freeze Frame/Failure Records 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 3

Go to Diagnostic

Aids

3

1. Turn OFF the ignition.

2. Disconnect the mass air flow (MAF) sensor.

3. Start the engine.

4. Observe the MAF Sensor parameter with a scan

tool.

Is the MAF Sensor parameter more than the specified
value?

0 Hz

Go to Step 4

Go to Step 5

4

1. Turn OFF the ignition.

2. Inspect the harness of the MAF sensor for

incorrect routing that is too close to the
following components:

z

Any aftermarket accessories-Refer to
Checking Aftermarket Accessories in
Wiring Systems.

z

The secondary ignition wires or the coils

-

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 P0106 (WITH THROTTLE ACTUATOR CONTROL)

z

Any solenoids

z

Any relays

z

Any motors

Did you find and correct the condition?

Go to Step 10

Go to Step 7

5

1. Turn OFF the ignition.

2. Inspect the air induction system for any water

intrusion.

Did you find and correct the condition?

-

Go to Step 10

Go to Step 6

6

Test for an intermittent and for a poor connection at the
MAF 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
powertrain control module (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

8

Replace the MAF/intake air temperature (IAT) sensor.
Refer to Mass Air Flow (MAF)/Intake Air
Temperature (IAT) Sensor Replacement .
Did you complete the replacement?

-

Go to Step 10

-

9

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

-

Go to Step 10

-

10

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 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