Hummer H1 Service Manual page 251

5-52 Transmission/Transfer Case
Step
1 1. Connect scan tool.
2. Turn the ignition switch to "on" position.
Important: Before clearing DTC(s), use the scan tool to record
"Failure Records" for reference, as data will be lost when the
"Clear Info" function is used.
3. Record the DTC "Failure Records."
NOTE: If any other DTCs are present, Refer to applicable diagnostic charts be-
fore continuing.
4. Using multimeter, measure the battery voltage across the battery terminals.
Record the measurement for future reference.
Is voltage higher than value shown?
2 Start the engine and warm to normal operating temperature.
Is generator charging (see voltmeter)?
3 1. Increase engine speed to 1500 rpm.
2. Observe scan tool system voltage.
Is system voltage within specified range?
4 1. Turn the ignition switch "off."
2. Disconnect PCM connector (additional DTCs will set).
3. With engine "off," turn the ignition switch "on."
4. Using the multimeter and Connector Test Adapter Kit, measure the battery
voltage input at PCM connector terminal "J3-C13."
Is there a voltage variance between the voltage measured at the battery (taken in
Step 2) and at terminal "J3-C13" that is greater than the value shown?
5 Repair high resistance condition in.
Was the circuit repaired?
6 1. Disconnect PCM connector.
2. Measure ignition voltage input at PCM connector terminals.
Is there a voltage variance between voltage measured at the battery (taken in
Step 2) and at terminal that is greater than value shown?
7 Repair high resistance condition in circuit 439.
Was the circuit repaired?
8 Check PCM connector terminals for bent, damaged, or backed out connector
pins. Also check for weak terminal tension.
Was a problem found?
9 Replace PCM.
Is replacement complete?
10 1. After the repair is complete, use the scan tool to select "DTC," then Unclear
Info" function.
2. Select Specific DTC" and enter DTC "P0560."
3. Operate the vehicle under the following conditions:
• Start the vehicle and warm to normal operating temperature. The PCM
must see a system voltage between 8.3 and 18.9 volts.
_____________________________________________
DTC P0560 System Voltage Fault
Action Value Yes
10.5
volts
Go to Check
Step 2 Battery
Check
12-14
charging Go to
volts
system Step 4
Check
13-15
Go to charging
volts
Step 4 system
0.5
volts
Go to Go to
Step 5 Step 5
Go to
—
Step 10
0.5
volts
Go to Go to
Step 7 Step 8
Go to
—
Step 10
— Go to Go to
Step 10 Step 9
Go to
Step 11
—
—
®
No
—
—
—
—