Hummer H2. Manual - part 1603

Do the misfire current counters increment for most
cylinders on one bank of the engine?

Go to Step 12

Go to Step 7

1. Inspect the spark plug wire for open circuits,

cracks, or improper seating of terminals at the
spark plug or coil before proceeding with test.
Refer to Spark Plug Wire Inspection .

2. Inspect for spark at the plug with the J 26792

Spark Tester or equivalent while cranking. A
few sparks, then nothing is considered no
spark.

Is adequate spark present?

Go to Step 33

Go to Step 8

Measure the spark plug wire resistance. Refer to
Spark Plug Wire Inspection .
Is the resistance more than the specified value?

1,000

ohm/ft

Go to Step 32

Go to Step 9

1. Turn OFF the ignition.

2. Disconnect the inoperative ignition coil.

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

4. Probe the ignition 1 voltage circuit of the

ignition coil with a test lamp connected to a
good ground. Refer to Probing Electrical
Connectors in Wiring Systems.

Does the test lamp illuminate?

Go to Step 10

Go to Step 13

Probe the ignition 1 voltage circuit at the ignition
coil with a test lamp connected to the ground circuit
of the ignition coil. Refer to Probing Electrical
Connectors in Wiring Systems.
Does the test lamp illuminate?

Go to Step 11

Go to Step 14

Probe the ignition 1 voltage circuit at the ignition
coil with a test lamp connected to the low reference
circuit of the ignition coil. Refer to Probing
Electrical Connectors in Wiring Systems.
Does the test lamp illuminate?

Go to Step 20

Go to Step 15

Inspect for an open INJ 1 or INJ 2 fuse.
Is the fuse open?

Go to Step 29

Go to Step 23

1. Disconnect the main ignition coil 8-way

connector.

2. Probe the ignition 1 voltage circuit at the

ignition coil main 8-way connector using the
test lamp connected to battery ground. Refer to
Probing Electrical Connectors in Wiring
Systems.

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls (Troubleshooting) - 4.8L, 5.3L, and 6.0L - Hummer H2

Does the test lamp illuminate?

Go to Step 24

Go to Step 23

1. Disconnect the main ignition coil 8-way

connector.

2. Probe the ignition 1 voltage circuit on the

harness side with a test lamp connected to the
ground circuit of the ignition coil. Refer to
Probing Electrical Connectors in Wiring
Systems.

Does the test lamp illuminate?

Go to Step 18

Go to Step 26

1. Disconnect the main ignition coil 8-way

connector.

2. Probe the ignition 1 voltage circuit on the

harness side with a test lamp connected to the
low reference circuit of the ignition coil. Refer
to Probing Electrical Connectors in Wiring
Systems.

Does the test lamp illuminate?

Go to Step 19

Go to Step 28

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

2. Disconnect the crankshaft position (CKP)

sensor.

3. Measure the voltage from the CKP sensor 12-

volt reference circuit and a good ground with
the DMM.

4. Compare the measured voltage with the

system voltage.

Is the difference in the voltage more than the
specified value?

0.5 V

Go to Step 17

Go to Step 30

Test for a short to ground in the CKP 12-volt
reference circuit or the camshaft position (CMP)
sensor 12-volt reference circuit. Refer to Circuit
Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 35

Go to Step 22

Test for an intermittent and for a poor connection at
the ignition coil 8-way 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 35

Go to Step 25

Test for an intermittent and for a poor connection at
the ignition coil 8-way connector. Refer to Testing
for Intermittent Conditions and Poor

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls (Troubleshooting) - 4.8L, 5.3L, and 6.0L - Hummer H2

Connections and Connector Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 35

Go to Step 27

Test for an intermittent and for a poor connection at
the ignition coil. 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 35

Go to Step 31

Test for an intermittent and for a poor connection at
the CKP 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 35

Go to Step 30

Test for an intermittent and for a poor connection at
the powertrain control module (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 35

Go to Step 34

Repair the open or high resistance in the ignition 1
voltage circuit between the fuse block and the splice.
Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?

Go to Step 35

Repair the open or high resistance in the ignition 1
voltage circuit between the splice and the ignition
coil connector. Refer to Wiring Repairs in Wiring
Systems.
Did you complete the repair?

Go to Step 35

Repair the open in the ground circuit between the
main 8-way connector and the ignition coil. Refer to
Wiring Repairs in Wiring Systems.
Did you complete the repair?

Go to Step 35

Repair the open in the ground circuit. Refer to
Wiring Repairs in Wiring Systems.
Did you complete the repair?

Go to Step 35

Repair the open in the low reference circuit between
the main 8-way connector and the ignition coil.
Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?

Go to Step 35

Repair the open in the low reference circuit between
the PCM and the splice. Refer to Wiring Repairs in
Wiring Systems.
Did you complete the repair?

Go to Step 35

1. Repair the ignition 1 voltage for a short to

ground. Refer to Wiring Repairs in Wiring

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls (Troubleshooting) - 4.8L, 5.3L, and 6.0L - Hummer H2

INSPECTION/MAINTENANCE (I/M) SYSTEM CHECK

Description

Several states require that a vehicle pass on-board diagnostic (OBD) system tests and the
inspection/maintenance (I/M) emission inspection in order to renew license plates. This is accomplished by
viewing the I/M System Status display on a scan tool. Using a scan tool, the technician can observe the I/M
System Status in order to verify that the vehicle meets the criteria that comply with the local area requirements.

Conditions for Updating the I/M System Status

Each system monitor requires at least one, and sometimes several diagnostic tests. The result of each test is
reported by a diagnostic trouble code (DTC). A system monitor is complete when either all of the DTCs
comprising the monitor have Run and Passed, or when any one of the DTCs comprising the monitor has
illuminated the malfunction indicator lamp (MIL). Once the system monitor is complete, the I/M System Status

Systems.

2. Replace the fuse.

Did you complete the repair?

Go to Step 35

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

Go to Step 35

Replace the ignition coil. Refer to Ignition Coil(s)
Replacement .
Did you complete the replacement?

Go to Step 35

Replace the spark plug wire. Refer to Spark Plug
Wire Replacement .
Did you complete the replacement?

Go to Step 35

Replace the spark plug. Refer to Spark Plug
Replacement .
Did you complete the replacement?

Go to Step 35

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

Go to Step 35

Attempt to start the engine.
Does the engine start and continue to run?

Go to Step 36

Go to Step 3

1. Clear the DTCs with a scan tool.

2. Turn OFF the engine for 30 seconds.

3. Start the engine.

4. Allow the engine to reach operating

temperature.

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 (Troubleshooting) - 4.8L, 5.3L, and 6.0L - Hummer H2

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