Hummer H2. Manual — part 1507

System Status to YES. The I/M System Status display on the scan tool provides an indication of whether the
control module has completed the required tests. The I/M System Status does not indicate that the tests have
passed or failed. When all of the diagnostics for a specific system have run and passed, the I/M System Status
will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES,
indicating a determination was made, even if all of the other tests for that system have not run.

Conditions for Running

z

DTCs P0135, P0141, P0155, P0161 are not set.

z

The engine has been running for more than 2 minutes.

z

The engine coolant temperature (ECT) is more than 50°C (122°F).

z

The engine speed is between 500-3,000 RPM.

z

The battery voltage is between 10-18 volts.

z

The mass air flow (MAF) is between 3-40 grams per second.

Diagnostic Aids

The HO2S Heater Tests will normally run within the 2 minutes allotted in the procedure. If there is an
indeterminate condition, the test may take up to 8 minutes on some vehicles before a decision of pass or fail is
made. If the test does not update to YES, it may have failed or aborted due to the loss of enabling conditions.
Extremely high ambient temperatures may prevent the HO2S Heater Test from initiating.

If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the
set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan
tool data list and the service information for an indication of why the test does not complete. Some tests may
abort due to changes in the conditions while the test is running. For example, changes in engine load such as a
cooling fan or A/C compressor clutch turning ON may cause the test to abort.

Inspection/Maintenance (I/M) Heated Oxygen Sensor (HO2S) Heater System Set Procedure

Step

Action

Value

(s)

Yes

No

1

Did you perform the Inspection/Maintenance
(I/M) System Check?

-

Go to Step 2

Go to

Inspection/Maintenance

(I/M) System Check

1. Preprogram the scan tool with the vehicle

information before the ignition is turned

IMPORTANT:

Whenever the ignition is turned ON,
ignition positive voltage is supplied to
the heated oxygen sensor (HO2S)
heaters. After verifying the enable
criteria, turn OFF the ignition for
approximately 5 minutes to allow the
sensors to cool before continuing with
the test.

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls (Troubleshooting) - 4.8L, 5.3L, and 6.0L - Hummer H2

2

ON.

2. Ensure the vehicle is within the

Conditions for Running as specified in
the supporting text.

3. Set the vehicle parking brake.

4. Verify the transmission is in Park for

automatic transmissions and Neutral for
manual transmissions.

5. Turn OFF all of the accessories, e.g.,

A/C, blower fan, etc.

6. Start the engine and allow it to idle for

the specified time or until the I/M System
Status indicator updates to YES.

Did the HO2S Heater System Status update to
YES?

2

minutes

Go to Step 5

Go to Step 3

3

Observe the DTC information with a scan tool.
Does the scan tool indicate any failed DTCs?

-

Go to

Diagnostic

Trouble

Code (DTC)

List

Go to Step 4

4

1. Refer to the Inspection/Maintenance

(I/M) System DTC Table to determine
which DTCs are required to run in order
to complete this test.

2. Observe the Not Ran Since Code Cleared

display with a scan tool.

3. Determine which of the DTCs required

for a YES status has not run.

4. Enter the DTC number in the Specific

DTC menu of the scan tool.

5. Operate the vehicle within the Conditions

for Running the DTC, located in the
supporting text for the diagnostic table of
the DTC.

6. Repeat the procedure until the scan tool

indicates the diagnostic test has run.

7. Repeat steps 4-6 for any additional

required DTCs that have not run.

8. Observe the I/M System Status display

with a scan tool.

Did the HO2S Heater System Status update to

-

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls (Troubleshooting) - 4.8L, 5.3L, and 6.0L - Hummer H2

YES?

Go to Step 5

Go to Diagnostic Aids

5

Observe the Emission Related DTC portion of
the I/M System Status display with a scan tool.
Does the scan tool indicate any Emission
Related DTCs set?

-

Go to

Diagnostic

Trouble

Code (DTC)

List

System OK

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls (Troubleshooting) - 4.8L, 5.3L, and 6.0L - Hummer H2

2004 ENGINE PERFORMANCE

Engine Controls (Diagnostic Information & Procedures) - 4.8L, 5.3L, and 6.0L - Hummer H2

DIAGNOSTIC STARTING POINT - ENGINE CONTROLS

Begin the system diagnosis with Diagnostic System Check - Engine Controls . The Diagnostic System
Check-Engine Controls will provide the following information:

z

The identification of the control modules which command the system

z

The ability of the control modules to communicate through the serial data circuit

z

The identification of any stored diagnostic trouble codes (DTCs) and the codes' statuses

The use of the Diagnostic System Check-Engine Controls will identify the correct procedure for diagnosing the
system and where the procedure is located.

DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS

DESCRIPTION

The Diagnostic System Check is an organized approach to identifying a condition created by an electronic
engine control system malfunction. The Diagnostic System Check must be the starting point for any driveability
concern. The Diagnostic System Check directs the service technician to the next logical step in diagnosing the
concern. Understanding the table and using the table correctly reduces diagnostic time and prevents the
replacement of good parts.

Diagnostic System Check - Engine Controls

Step

Action

Yes

No

1

Perform the following preliminary
inspections:

1. Ensure that the battery is fully

charged. Refer to Battery
Inspection/Test (Non-HP2) in
Engine Electrical.

2. Ensure that the battery cables are

clean and tight.

3. Inspect the easily accessible

systems or the visible system
components for obvious damage or
conditions that could cause the
symptom. Refer to Strategy Based
Diagnosis in General Information

4. Ensure that the engine and control

module grounds are clean, tight,

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls (Diagnostic Information & Procedures) - 4.8L, 5.3L, and 6.0L -

Hummer H2

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls (Diagnostic Information & Procedures) - 4.8L, 5.3L, and 6.0L -

Hummer H2