Hummer H2. Manual - part 1534

condition?

Go to Step 17

Go to Step 14

Test the HO2S low signal 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 17

Go to Step 14

1. The HO2S may be detecting a rich exhaust

condition or may be contaminated. Inspect for
the following conditions:

A silicon contaminated HO2S

Any water intrusion into the HO2S
connector

Engine oil contaminated with fuel

An evaporative emission (EVAP) canister
purge condition

An incorrect fuel pressure-Refer to Fuel
System Diagnosis .

Any rich fuel injectors-Refer to Fuel
Injector Balance Test with Tech 2 .

An inaccurate mass air flow (MAF)
sensor-Refer to Scan Tool Data List .

An air intake restriction or collapsed air
intake duct

2. Repair any of the above or similar engine

conditions as necessary.

Did you find and correct the condition?

NOTE:

Refer to Silicon Contamination of
Heated Oxygen Sensors Notice in
Cautions and Notices.

Go to Step 17

Go to Step 13

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 17

Go to Step 15

Test for shorted terminals and for poor connections 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 17

Go to Step 16

Replace the affected HO2S. Refer to Heated Oxygen

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 P0133 OR P0153

Circuit Description

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the
oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach
operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the
time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the
HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the PCM operates in
open loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and closed loop is
achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias
voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream.
This diagnostic will only run once per ignition cycle. The PCM monitors the rich-to-lean and lean-to-rich
transition time. A transition is defined as, the HO2S voltage changes from above 625 mV to below 250 mV or
from below 250 mV to above 625 mV. If the PCM detects that the transition time is too long, DTC P0133 sets
for HO2S bank 1 sensor 1, or DTC P0153 sets for HO2S bank 2 sensor 1.

Conditions for Running the DTC

DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120,
P0131, P0132, P0134, P0135, P0151, P0152, P0154, P0155, P0200, P0220, P0300, P0442, P0446,
P0452, P0453, P0455, P0496, P1125, P1258,P1516, P2101, P2108, P2135, U0107 are not set.

The ECT Sensor parameter is more than 60°C (140°F).

The EVAP Purge Solenoid Command parameter is more than 1 percent.

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

Go to Step 17

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

Go to Step 17

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 18

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 MAF Sensor parameter is between 20-55 g/s.

The Engine Speed parameter is between 1,200-3,000 RPM.

The TP Indicated Angle parameter is 5 percent more than the value observed at idle.

The Loop Status parameter is closed.

The Ignition 1 Signal parameter is between 10-18 volts.

The Fuel Tank Level Remaining parameter is more than 10 percent.

The Engine Run Time parameter is more than 160 seconds.

The above conditions are met for 100 seconds.

Conditions for Setting the DTC

The PCM detects that the affected HO2S rich-to-lean or lean-to-rich average response time is more than a
calibrated value.

Action Taken When the DTC Sets

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

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

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

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

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

Clear the MIL and the DTC with a scan tool.

Test Description

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

2: If the voltage is varying above and below the specified value, the condition is not present.

DTC P0133 or P0153

Step

Action

Value

(s)

Yes

Schematic Reference:Engine Controls Schematics
Connector End View Reference:Engine Controls Connector End Views or Powertrain Control

2004 Hummer H2

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

Hummer H2

Module (PCM) Connector End Views

Did you perform the Diagnostic System Check-Engine
Controls?

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls

1. Start the engine.

2. Allow the engine to reach operating temperature.

Refer to Scan Tool Data List .

3. Operate the engine at 1,500 RPM for 30 seconds.

4. Observe the affected HO2S voltage parameter

with a scan tool.

Is the HO2S voltage parameter varying above and
below the specified range?

250-

625
mV

Go to Step 3

Go to Step 4

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 4

Go to

Intermittent

Conditions

1. Turn OFF the ignition.

2. Disconnect the affected heated oxygen sensor

(HO2S).

3. Connect a 3-amp fused jumper wire between the

high signal circuit of the HO2S harness
connector on the engine harness side and a good
ground.

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

5. Observe the HO2S voltage parameter with a scan

tool.

Is the HO2S voltage parameter less than the specified
value?

100
mV

Go to Step 6

Go to Step 5

Test the HO2S high signal 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 12

Go to Step 9

1. Remove the jumper wire from the previous step.

2. Connect a 3-amp fused jumper wire between the

2004 Hummer H2

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

Hummer H2

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