Hummer H2. Manual - part 1655

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

5: This step tests the CMP sensor signal circuit. Applying a voltage causes the CMP sensor high to low
and low to high parameter to increase if the circuit and the PCM are operating properly.

DTC P0342

Step

Action

Yes

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. Start the engine.

2. Observe the camshaft position (CMP) sensor high to

low and low to high transition parameter with a scan
tool.

Does the scan tool parameter increment?

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 Diagnostic

Aids

1. Turn OFF the ignition.

2. Disconnect the CMP sensor.

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

4. Probe the 12-volt reference circuit of the CMP sensor

at the CMP sensor wire harness electrical connector
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 5

Go to Step 6

1. Start the engine.

2. Observe the CMP sensor high to low and low to high

transition parameters with the scan tool.

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

3. Momentarily and repeatedly probe the signal circuit of

the CMP sensor at the CMP sensor wire harness
electrical connector with a test lamp that is connected
to battery positive voltage.

Does the CMP sensor high to low and low to high transition
counters increment when the test lamp contacts the signal
circuit?

Go to Step 8

Go to Step 7

Test the 12-volt reference 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 14

Go to Step 9

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

Go to Step 14

Go to Step 9

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 14

Go to Step 10

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 14

Go to Step 13

1. Remove the CMP sensor. Refer to Camshaft Position

(CMP) Sensor Replacement .

2. Visually inspect the CMP sensor for the following

conditions:

Physical damage

Loose or improper installation

Wiring routed too close to the secondary ignition
components

Did you find and correct the condition?

Go to Step 14

Go to Step 11

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 14

Go to Step 12

Replace the CMP sensor. Refer to Camshaft Position

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 P0343

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
stroke and re-syncs to the opposite cam position. If the PCM detects that the CMP signal is constantly high,
DTC P0343 sets.

Conditions for Running the DTC

The engine is running.

The engine speed is less than 4,000 RPM.

Conditions for Setting the DTC

(CMP) Sensor Replacement .
Did you complete the replacement?

Go to Step 14

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

Go to Step 14

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 15

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

The PCM detects that the CMP sensor signal is high 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.

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 the condition is intermittent, refer to Intermittent Conditions .

Test Description

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

5: This step tests the CMP sensor signal circuit. Applying a voltage causes the CMP sensor high to low
and low to high parameter to increase if the circuit and the PCM are operating properly.

DTC P0343

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or
Powertrain Control Module (PCM) Connector End Views

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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