Content .. 1554 1555 1556 1557 ..

Hummer H2. Manual - part 1556

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 signal circuit of the CMP sensor 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 7

Go to

Step 5

1. Start the engine.

2. Observe the CMP sensor high to low and low

to high transition parameters with the scan tool.

3. Momentarily and repeatedly probe the signal

circuit of the CMP sensor with a test lamp that
is connected to battery 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 6

Go to Step 10

1. Turn OFF the ignition.

2. Jumper the CMP circuits from the CMP sensor

to the CMP sensor harness connector. Refer to
Using Connector Test Adapters in Wiring

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

Systems.

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

4. Measure the Voltage Drop from the low

reference circuit of the CMP sensor to a good
ground with a DMM. Refer to Circuit Testing
in Wiring Systems.

Is the voltage more than the specified value?

0.2 V

Go to

Step 8

Go to

Step 9

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

Go to Step 15

Go to Step 10

Test the low 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 15

Go to Step 10

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 15

Go to Step 11

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 15

Go to Step 14

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 15

Go to Step 12

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 15

Go to Step 13

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 P0351-P0358

Circuit Description

The ignition system on this engine uses an individual ignition coil for each cylinder. The powertrain control
module (PCM) controls the ignition system operation. The PCM controls each coil using one of eight ignition
control (IC) circuits. The PCM commands the IC circuit low when a spark event is requested. This causes the
IC module to energize the ignition coil to create a spark at the spark plug. Each ignition coil has the following
circuits:

An ignition 1 voltage circuit

A ground circuit

An ignition control (IC) circuit

A low reference circuit

Sequencing and timing are PCM controlled. If the PCM detects that the IC circuit is out of range, DTC P0351-
P0358 sets.

Conditions for Running the DTC

The engine is operating.

Conditions for Setting the DTC

The PCM detects the IC circuit is grounded, open, or shorted to voltage for less than 1 second.

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

Go to Step 15

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

Go to Step 15

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 16

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

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.

3: This step verifies the integrity of the IC circuit and the PCM output.

4: This step tests for a short to ground on the IC circuit.

DTC P0351-P0358

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

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 you observed
from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 3

Go to Intermittent

Conditions

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

Content .. 1554 1555 1556 1557 ..