Hummer H2. Manual - part 1120

SYMPTOMS - ENGINE ELECTRICAL 

z

Perform Diagnostic System Check - Engine Electrical before using the Symptom Tables in order to 

3

engine OFF.  

2. Disconnect the generator harness 

connector.  

3. Measure the voltage between the 

generator turn on signal circuit and 
ground.  

Does the voltage measure near the specified 
value?

10-11 

volts

Go to Step 5

Go to Step 4

4

Test the generator turn on signal circuit for a 
short or open. Refer to Circuit Testing and 
Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 8

Go to Step 6

5

Inspect for poor connections at the harness 
connector of the generator. Refer to 
Connector Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 8

Go to Charging 

System Test 

(CS/AD/SI 

Generators)

6

Inspect for poor connections at the harness 
connector of 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 8

Go to Step 7

7

Replace the PCM/ECM. Refer to 
Powertrain Control Module (PCM) 
Replacement in Engine Controls 4.8L, 
5.3L, and 6.0L.Is action complete?

IMPORTANT:

The replacement PCM must be 
programmed.

-

Go to Step 8

-

8

1. Use the scan tool in order to clear the 

DTCs.  

2. Operate the vehicle within the 

Conditions for Running the DTC as 
specified in the supporting text.  

Does the DTC reset?

-

Go to Step 2

System OK

IMPORTANT: The following steps must be completed before using the symptom tables.

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2

  

verify that all of the following are true: 

{

There are no DTCs set.  

{

The control module(s) can communicate via the serial data link.  

z

Review the system operation in order to familiarize yourself with the system functions. Refer to one of 
the following system operations: 

{

Battery Description and Operation  

{

Starting System Description and Operation  

{

Charging System Description and Operation  

Visual/Physical Inspection 

z

Inspect for aftermarket devices which could affect the operation of the Starting and Charging Systems. 
Refer to Checking Aftermarket Accessories in Wiring Systems.  

z

Inspect the easily accessible or visible system components for obvious damage or conditions which could 
cause the symptom.  

Intermittent 

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for 
Intermittent Conditions and Poor Connections in Wiring Systems. 

Symptom List 

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom: 

z

Starter Solenoid Does Not Click  

z

Starter Solenoid Clicks, Engine Does Not Crank  

z

Engine Cranks Slowly  

z

Battery Inspection/Test (Non-HP2)  

z

Charge Indicator Always On  

z

Charge Indicator Inoperative  

z

Charging System Test (CS/AD/SI Generators)  

z

Generator Noise Diagnosis  

BATTERY INSPECTION/TEST (NON-HP2) 

Diagnostic Aids 

CAUTION: Refer to Battery Disconnect Caution in Cautions and Notices.

IMPORTANT:

z

The battery test using the J 42000 Battery Tester requires correct 

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2

  

Follow these instructions in order to avoid an incorrect diagnosis because of connections: 

z

If testing the vehicle with the battery cables still connected, wiggle the J 42000 clips on the terminal bolt. 
This may cut through any coating or through any oxidation that may be present on the bolt. See Special 
Tools and Equipment . 

Even new bolts contain a protective coating that may insulate or cause a resistance in the test circuit. 

z

If correct connections to the battery terminal bolts in the vehicle are in doubt, perform the following 
steps: 

1. Disconnect the negative battery cable.  

2. Disconnect the positive battery cable.  

3. Install the test adapters on the terminals.  

4. Follow the instructions for testing a removed battery.  

z

If the tester displays a REPLACE BATTERY or BAD CELL-REPLACE result for a battery tested in the 
vehicle with the battery cables connected, perform the following steps: 

1. Disconnect the negative battery cable.  

2. Disconnect the positive battery cable.  

3. Install the tester adapters. 

4. Follow the instructions for testing a removed battery.  

5. Replace the battery only if the second test shows a REPLACE BATTERY or BAD CELL-

REPLACE result. 

Use the test code from the second test for any warranty purposes. 

z

Use the correct terminal adapters. 

Do not use any common bolts or a combination of bolts, of nuts, and of washers as adapters when testing 
the battery. 

connections to the battery terminals. A failure to obtain the correct 
connections during the test may result in a failed test on a good battery. 
See Special Tools and Equipment .  

z

Use the Out of Vehicle test for each battery when testing a vehicle with 
dual batteries.  

IMPORTANT: Always write the test code displayed by the tester on the repair order 

for any warranty purposes. The number is a unique code that 
describes the test data for a particular battery at a particular time. 
The test code may occasionally repeat when you retest the same 
battery. More often, each test will result in a different code. Use the 
test code from the second, or Out of Vehicle test.

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2

  

Use the test adapters that are provided with the J 42000 or GM P/N 12303040 terminal adapters. If the 
adapters that are provided with the J 42000 require replacement, use GM P/N 12303040. Any other 
adapter may not contact the correct areas of the battery terminal, causing a resistance that may result in an 
invalid battery test result. See Special Tools and Equipment . 

Battery Inspection/Test (Non-HP2) 

Step

Action

Value(s)

Yes

No

CAUTION:

Refer to Battery Disconnect Caution in Cautions and Notices.

1

Inspect the battery for a cracked, broken, or damaged case, which may 
be indicated by battery acid leakage. 
Is the battery OK?

-

Go to 

Step 2

Go to 

Step 

19

2

Compare the Cold Cranking Amperage (CCA) and Reserve Capacity 
(RC) of the battery to the original battery or Original Equipment (OE) 
specification. Refer to Battery Usage . 
Does the battery meet or exceed the specifications?

-

Go to 

Step 3

Go to 

Step 

19

3

Does the hydrometer display a yellow dot?

-

Go to 

Step 4

Go to 

Step 5

4

Tap the hydrometer lightly on top with the handle of a small 
screwdriver in order to dislodge any air bubbles inside the battery. 
Does the hydrometer still display a yellow dot?

-

Go to 

Step 19

Go to 

Step 5

5

1. Turn OFF the ignition.  

2. Attempt to rotate the negative battery cable connector clockwise 

with light finger pressure.  

Does the negative connector rotate?

-

Go to 

Step 6

Go to 

Step 7

6

Use a torque wrench in order to verify the torque to loosen the 
negative battery terminal bolt. 
Is the torque above the specified value?

10 N.m 

(88 lb in)

Go to 

Step 8

Go to 

Step 7

7

Disconnect the negative battery cable. 
Is the cable disconnected?

-

Go to 

Step 9

-

8

1. Disconnect the negative battery cable.  

2. Inspect for the following conditions and repair as needed: 

z

The cable bolt is too long or deformed at the end.  

z

There is foreign material present inside the nut in the 
battery terminal.  

z

Damage to the battery terminal face or cable connector 
ring.  

Is the repair complete?

-

Go to 

Step 9

-

9

Rotate the positive battery cable connector clockwise with light finger 
pressure. 
Does the positive connector rotate?

-

Go to 

Step 10

Go to 

Step 

11

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2