Hummer H2. Manual - part 1654

The PCM detects that a CMP to CKP mis-match has occurred.

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.

Diagnostic Aids

The following conditions may cause this DTC to set:

Camshaft reluctor ring damage

The sensor coming in contact with the reluctor ring

Foreign material passing between the sensor and the reluctor ring

Excessive camshaft end-play

Wiring routed too close to secondary ignition components

If you suspect the condition is intermittent, refer to Intermittent Conditions .

Test Description

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

3: This step inspects for electromagnetic interference (EMI) on the CMP sensor circuits.

6: Damage to the face of the sensor could indicate foreign material passing between the CMP sensor and
the reluctor wheel. This condition would cause this DTC to set. Damage to the reluctor wheel would
affect the CMP sensor output.

DTC P0341

Step

Action

Yes

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

Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Powertrain Control
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. 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 3

Go to Diagnostic

Aids

1. Visually and physically inspect all circuits going to

the CMP sensor for the following:

Being routed too close to secondary ignition
wires or components

Being routed too close to after-market add-on
electrical equipment

Being routed too close to solenoids, relays,
and motors

2. If you find incorrect routing, correct the harness

routing

Did you find and correct the condition?

Go to Step 9

Go to Step 4

Test for an intermittent and for a poor connection at the
CMP sensor. 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 9

Go to Step 5

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 9

Go to Step 6

1. Remove the CMP sensor. Refer to Camshaft

Position (CMP) Sensor Replacement .

2. Visually inspect the CMP sensor for the following

conditions:

Physical damage

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

DTC P0342

Circuit Description

The camshaft position (CMP) sensor works in conjunction with a 1 X reluctor wheel on the camshaft. The
powertrain control module (PCM) provides a 12 volt reference to the CMP sensor as well as a low reference
and a signal circuit.

As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor.
The sensors internal circuitry detects this and produces a signal which the PCM reads.

The CMP sensor 1 X signal is used by the PCM to determine if the cylinder at top dead center (TDC) is on the
firing stroke or the exhaust stroke. The PCM can determine TDC for all cylinders by using the CKP sensor 24 X
signal alone. The engine will start without a CMP signal as long as the PCM receives the CKP sensor 24 X
signal. A slightly longer cranking time may be a symptom of this condition. The system attempts
synchronization and looks for an increase in engine speed indicating that the engine started. If the PCM does
not detect an increase in engine speed, the PCM assumes that the PCM incorrectly synchronized to the exhaust

Excessive wear of the sensor

Loose or improper installation

Did you find and correct the condition?

Go to Step 9

Go to Step 7

1. Visually inspect the CMP sensor reluctor ring for

damage.

2. If the CMP reluctor ring is damaged, Refer to

Camshaft and Bearings Cleaning and Inspection
in Engine Mechanical.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

Replace the CMP sensor. Refer to Camshaft Position
(CMP) Sensor Replacement .
Did you complete the replacement?

Go to Step 9

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 10

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

stroke and re-syncs to the opposite cam position. If the PCM detects that a CMP signal is constantly low, DTC
P0342 sets.

Conditions for Running the DTC

The engine is running.

The engine speed is less than 4,000 RPM.

Conditions for Setting the DTC

The PCM detects that the CMP sensor signal is low for 1.5 seconds.

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.

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.

Diagnostic Aids

The following conditions may cause this DTC to set:

Camshaft reluctor ring damage

The sensor coming in contact with the reluctor ring

Foreign material passing between the sensor and the reluctor ring

Excessive camshaft end-play

Wiring routed too close to secondary ignition components

If the condition is intermittent, refer to Intermittent Conditions .

Test Description

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

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