Hummer H2. Manual - part 369

Action Taken When the DTC Sets

The PCM records the operating conditions at the time the diagnostic test fails. The PCM displays this
information in the Failure Records on the scan tool.

The instrument panel cluster (IPC) illuminates the engine oil pressure indicator.

Conditions for Clearing the DTC

The DTC becomes history when the conditions for setting the DTC are no longer present.

The history DTC clears after 40 malfunction free warm-up cycles.

The PCM receives a clear code command from the scan tool.

Diagnostic Aids

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the
information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and
Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

4: This step tests for the proper operation of the circuit in the high voltage range.

DTC P0522

Step

Action

Values

Yes

Schematic Reference: Instrument Cluster Schematics

Did you perform the Instrument Cluster Diagnostic
System Check?

Go to Step 2

Go to Diagnostic

System Check -

Instrument Cluster

1. Install a scan tool.

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

3. With the scan tool, observe the Engine Oil

Pressure Sensor parameter in the PCM Engine
Data 2 data list.

Does the Engine Oil Pressure Sensor parameter
display less than the specified value?

0.4 V

Go to Step 3

Go to Diagnostic

Aids

Is DTC P0641 current in the PCM?

Go to DTC

P0641 in

Engine

Controls

Go to Step 4

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Instrument Panel, Gauges, and Console - Hummer H2

1. Turn the ignition OFF.

2. Disconnect the engine oil pressure (EOP)

sensor.

3. Connect a 3-ampere fused jumper between the

EOP sensor signal circuit and the 5 volt
reference circuit of the EOP sensor.

4. With the scan tool, observe the Engine Oil

Pressure Sensor parameter.

Does the Engine Oil Pressure Sensor parameter
display greater than the specified value?

4.6 V

Go to Step 8

Go to Step 5

1. Disconnect the fused jumper.

2. Measure the voltage between the 5 volt

reference circuit of the EOP sensor and the low
reference circuit of the EOP sensor.

Does the voltage measure greater than the specified
value?

4.6 V

Go to Step 7

Go to Step 6

Test the 5 volt reference circuit of the EOP sensor for
an open or for a high resistance. Refer to Circuit
Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 12

Go to Step 9

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

Go to Step 12

Go to Step 9

Inspect for poor connections at the harness connector
of the EOP sensor. Refer to Testing for Intermittent
Conditions and Poor Connections and to
Connector Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 12

Go to Step 10

Inspect for poor connections at the harness connector
of the PCM. Refer to Testing for Intermittent
Conditions and Poor Connections and to
Connector Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 12

Go to Step 11

Replace the EOP sensor. Refer to Engine Oil
Pressure Sensor and/or Switch Replacement in
Engine Mechanical.
Did you complete the replacement?

Go to Step 12

IMPORTANT:

Program the replacement PCM.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Instrument Panel, Gauges, and Console - Hummer H2

DTC P0523

Circuit Description

The engine oil pressure (EOP) sensor changes resistance based on engine oil pressure. The PCM monitors the
signal circuit of the EOP sensor. When the oil pressure is high, the sensor resistance is high, and the PCM
senses a high signal voltage. When the oil pressure is low, the sensor resistance is low, and the PCM senses a
low signal voltage. The PCM sends the engine oil pressure information to the IPC via the class 2 serial data
circuit.

Conditions for Running the DTC

The engine is running.

DTC P0641 is not present.

Conditions for Setting the DTC

The PCM detects that the EOP sensor signal circuit is greater than 4.6 volts.

The above condition is present for greater than 9 seconds.

Action Taken When the DTC Sets

The PCM records the operating conditions at the time that the diagnostic test fails. The PCM displays this
information in the Failure Records on the scan tool.

Conditions for Clearing the DTC

The DTC becomes history when the conditions for setting the DTC are no longer present.

The history DTC is cleared after 40 malfunction-free warm-up cycles.

The PCM receives the clear code command from the scan tool.

Diagnostic Aids

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the
information in the Failure Records can help in determining how many miles since the DTC set. The Fail
Counter and the Pass Counter can help determine how many ignition cycles that the diagnostic test reported a

Replace the PCM. Refer to Powertrain Control
Module (PCM) Replacement in Engine Controls-
6.0L (LQ4).Did you complete the replacement?

Go to Step 12

1. Use the scan tool in order to clear the DTCs.

2. Operate the vehicle within the Conditions for

Running the DTC.

Does the DTC reset?

Go to Step 2

System OK

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Instrument Panel, Gauges, and Console - Hummer H2

pass and/or a fail.

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

3: This step tests for the proper operation of the circuit in the low voltage range.

DTC P0523

Step

Action

Values Yes

Schematic Reference: Instrument Cluster Schematics

Did you perform the Instrument Cluster Diagnostic System
Check?

Go to

Step 2

Go to Diagnostic

System Check -

Instrument Cluster

1. Install a scan tool.

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

3. With the scan tool, observe the Engine Oil Pressure

Sensor parameter in the PCM Engine Data 2 data list.

Does the Engine Oil Pressure Sensor parameter display
greater than the specified value?

4.6 V

Go to

Step 3

Go to Diagnostic

Aids

1. Turn the ignition OFF.

2. Disconnect the engine oil pressure (EOP) sensor.

3. With the scan tool, observe the Engine Oil Pressure

Sensor parameter.

Does the Engine Oil Pressure Sensor parameter display less
than the specified value?

0.4 V

Go to

Step 4

Go to Step 5

1. Turn the ignition OFF.

2. Disconnect the negative battery cable. Refer to Battery

Negative Cable Disconnect/Connect Procedure
(Single Battery) in Engine Electrical.

3. Measure the resistance from the low reference circuit of

the EOP sensor to a good ground.

Is the resistance less than the specified value?

5 ohm

Go to

Step 7

Go to Step 6

Test the EOP sensor signal circuit for a short to voltage. Refer
to Circuit Testing and to Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to

Step

Go to Step 8

1. Disconnect the PCM.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Instrument Panel, Gauges, and Console - Hummer H2

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