Hummer H2. Manual — part 1651

DTC P0327 OR P0332

Circuit Description

The knock sensors (KS) produce an AC signal under all engine operating conditions. When the engine is
running, the powertrain control module (PCM) learns a minimum and maximum frequency of normal engine
noise. The KS system monitors both knock sensors in order to determine if knock is present. If the KS system
determines that excessive knock is present, the PCM retards the spark timing based on the signals from the KS.
The PCM continues to retard timing until no knock is present. If the PCM detects that the frequency is out of
the normal range, DTC P0327 or P0332 will set.

Conditions for Running the DTC

z

DTCs P0116, P0117, P0118, P0122, P0123, P0125, or P0128 are not set.

z

The minimum noise level must be learned. The minimum noise level is learned when the following
conditions are met:

{

The engine coolant temperature (ECT) is more than 60°C (140°F).

{

The engine RPM is between 475-975 for 10 seconds.

z

The engine speed is between 1,500-3,000 RPM.

z

The manifold absolute pressure (MAP) is less than 45 kPa.

z

The engine run time is more than 10 seconds.

z

The ignition voltage is more than 10 volts.

2

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 Intermittent

Conditions

3

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

Go to Step 4

-

4

1. Start the engine.

2. 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 5

5

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 P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and

6.0L - Hummer H2

Conditions for Setting the DTC

The PCM detects that the affected KS signal is less than the expected amount for more than 9 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 KS for proper installation. A knock sensor that is loose or over torqued may cause the DTC to
set.

z

If DTCs P0327 and P0332 are set at the same time, inspect for poor connections at the KS harness
jumper, located at the left rear side of the intake manifold.

z

For an intermittent, refer to Intermittent Conditions .

DTC P0327 or P0332

IMPORTANT: If the KS is dropped, the sensor must be replaced.

Step

Action

Values

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

IMPORTANT:

If an engine knock can be heard, repair the engine
mechanical condition before proceeding with this
diagnostic.

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and

6.0L - Hummer H2

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 engine 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. Remove the intake manifold sight shield. Refer

to Engine Sight Shield Replacement (6.0L
(LQ4)) in Engine Mechanical.

3. Disconnect the knock sensor (KS) inline

harness connector.

4. Measure the resistance from the signal circuit

of the affected KS to a good ground with a
DMM.

Is the resistance of the KS within the specified range?

93K-

107K

ohm

Go to Step 4

Go to Step 6

4

1. Measure the AC voltage from the signal circuit

of the affected KS to a good ground.

2. Tap on the engine block near the affected KS

while observing the DMM.

Does the voltage change on the DMM while tapping
on the engine block near the KS?

IMPORTANT:

Do not tap on any plastic engine components.

-

Go to Step 5

Go to Step 10

5

Test the affected KS signal circuit between the PCM
and the KS inline harness connector for the following
conditions:

z

An open or a high resistance

z

A short to voltage

z

A short to ground

Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.

-

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and

6.0L - Hummer H2

Did you find and correct the condition?

Go to Step 12

Go to Step 8

6

1. Remove the intake manifold. Refer to Intake

Manifold Replacement in Engine Mechanical.

2. Test the affected signal circuit between the KS

inline harness connector and the affected KS
connector for an open, high resistance or short
to ground. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

-

Go to Step 12

Go to Step 7

7

Test for an intermittent and for a poor connection at
the affected KS. 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 12

Go to Step 10

8

Test for an intermittent and for a poor connection at
the KS inline harness connector. 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 12

Go to Step 9

9

Test for an intermittent and for a poor connection 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 12

Go to Step 11

10

Replace the affected knock sensor. Refer to Knock
Sensor (KS) Replacement .
Did you complete the replacement?

-

Go to Step 12

-

11

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

-

Go to Step 12

-

12

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 as specified in the
supporting text. You may also operate the
vehicle within the Freeze Frame/Failure
Records.

Did the DTC fail this ignition?

-

Go to Step 2

Go to Step 13

13

Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?

-

Go to

Diagnostic

Trouble Code

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and

6.0L - Hummer H2