Hummer H2. Manual — part 1643

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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

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

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

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

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Clear the MIL and the DTC with a scan tool.

Test Description

The number below refers to the step number on the diagnostic table.

9: With no fault present, the test lamp will blink once per second.

DTC P0141 or P0161

Step

Action

Value

(s)

Yes

No

Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Component 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. Turn ON the ignition, with the engine OFF.

2. Command the HO2S heaters ON with a scan

tool.

3. Wait 15 seconds to allow the HO2S heater

current to stabilize.

4. Observe the affected HO2S heater current

parameter with a scan tool.

Is the HO2S heater current parameter within the

IMPORTANT:

Whenever the HO2S heaters are commanded ON
with a scan tool, they will continue to be pulsed
ON once per second until the ignition is turned
OFF for 30 seconds.

0.25-

1.375

A

2004 Hummer H2

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

Hummer H2

specified range?

Go to Step 3

Go to Step 6

3

observe the Freeze Frame/Failure Records for this
DTC.
Did the DTC fail with an engine run time of less than
10 seconds?

-

Go to Step 4

Go to Step 5

4

1. Operate the vehicle within the Conditions for

Running the Heater Resistance Test.

2. Start the engine.

Did the DTC fail this ignition?

-

Go to Step 6

Go to Intermittent

Conditions

5

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 Heater Current Test. 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 6

Go to Intermittent

Conditions

6

Inspect the O2B fuse.
Is the O2B fuse open?

-

Go to Step 7

Go to Step 8

7

Test the ignition 1 voltage circuit for a short to
ground. Refer to Circuit Testing and Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 22

Go to Step 10

8

1. Disconnect the affected HO2S.

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

3. Probe the ignition 1 voltage circuit of the

HO2S harness connector on the engine harness
side with a test lamp that is connected to a
good ground. Refer to Probing Electrical
Connectors in Wiring Systems.

Does the test lamp illuminate?

-

Go to Step 9

Go to Step 19

IMPORTANT:

The test lamp may blink prior to commanding the
heaters ON. This is because the heaters were
commanded ON in a previous step. To command
the heaters OFF, turn OFF the ignition for 30
seconds.

2004 Hummer H2

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

Hummer H2

9

1. Connect a test lamp between the ignition 1

voltage circuit of the HO2S harness connector
on the engine harness side and the HO2S
heater low control circuit of the HO2S harness
connector on the engine harness side.

2. Command the HO2S heaters ON with a scan

tool.

Does the test lamp blink once per second?

-

Go to Step 11

Go to Step 12

10

Test the ignition 1 voltage circuit on the sensor side
of the HO2S connector for a short to ground. Refer
to Circuit Testing in Wiring Systems.Is any sensor
shorted to ground?

IMPORTANT:

Perform the following test on all HO2S' which are
supplied voltage by the suspect circuit.

-

Go to Step 20

Go to Intermittent

Conditions

11

Measure the resistance of the following circuits with
a DMM:

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HO2S heater low control circuit

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Ignition 1 voltage circuit

Refer to Circuit Testing in Wiring Systems.
Is the resistance of either circuit more than the
specified value?

3 ohm

Go to Step 18

Go to Step 16

12 Is the test lamp on steady?

-

Go to Step 13

Go to Step 14

13

Test the HO2S heater low control circuit for a short
to ground. Refer to Circuit Testing and Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 22

Go to Step 17

14

Test the HO2S heater low control circuit 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 22

Go to Step 15

15

Test the HO2S heater low control circuit for an open
or high resistance. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 22

Go to Step 17

16

Test for shorted terminals and for poor connections
at the HO2S. 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 22

Go to Step 20

2004 Hummer H2

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

Hummer H2

17

Test for shorted terminals and for poor connections
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 22

Go to Step 21

18

Repair the circuit with high resistance. Refer to
Wiring Repairs in Wiring Systems.
Did you complete the repair?

-

Go to Step 22

-

19

Repair the open or high resistance in the ignition 1
voltage circuit. Refer to Wiring Repairs in Wiring
Systems.
Did you complete the repair?

-

Go to Step 22

-

20

Replace the affected HO2S. Refer to Heated
Oxygen Sensor (HO2S) Replacement Bank 1
Sensor 2 or Heated Oxygen Sensor (HO2S)
Replacement Bank 2 Sensor 2 .
Did you complete the replacement?

-

Go to Step 22

-

21

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

-

Go to Step 22

-

22

Were you sent to this diagnostic from DTC P0140 or
P0160?

-

Go to Step 17 in

DTC P0140 or

P0160

Go to Step 23

23

1. Replace the O2B fuse if necessary.

2. Clear the DTCs with a scan tool.

3. Turn OFF the ignition for 30 seconds.

4. Start the engine.

5. 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 24

24

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