Hummer H1 Service Manual page 250

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DTC P0560 System Voltage Fault
Circuit Description
Circuit 239 is the voltage feed for the PCM. Circuit 537 is the
battery feed for the PCM.
This DTC detects a low voltage, a high voltage for a long time,
or a high voltage for a short time. This is a type "D" DTC.
Conditions For Setting DTC
System Voltage Low:
• Engine speed is greater than 1500 rpm.
• System voltage is less than 10.5 volts at a maximum
transmission temperature of 152° C (305° F).
• System voltage is less than 6.7 volts at a minimum
transmission temperature of -40° C (-40° F).
• All conditions met for 4 seconds.
System Voltage High:
• System voltage is greater than 19 volts for 4 seconds.
Action Taken When DTC Sets
• The PCM will cause an immediate shift to second gear.
• The PCM will turn off Pressure Control Solenoid.
• The PCM will inhibit converter clutch engagement.
• The PCM will freeze shift adapts.
• The PCM will NOT illuminate the Engine/Trans light.
05745159
HOT AT HOT IN RUN
ALL TIMES AND START
FUSE 2D FUSE 3A
20 AMP 20 AMP
INTERIOR EXTERIOR
C1-10
TO
C29-B3
C28-C13 C28-D13 C28-C12 C28-C11
BATT BATT IGN
GROUND GROUND
C28-D6 C28-D7
HOT AT
ALL TIMES
G2
Transmission/Transfer Case
HOT IN RUN
AND START
STS MIL
LAMP LAMP
C10-H C10-C
C3-G5 C3-F3
C1-25 C1-28
C28-D11 C28-C14
IGN STS LAMP MIL
CONTROL CONTROL
SERIAL DATA
CLASS II
C28-C8
59 BK
FUSE 1H
4
5 AMP
INTERIOR
G4
16
554 GRY
Conditions For Clearing DTC
• The DTC can be cleared using the scan tool. The DTC
will be cleared when the vehicle has achieved 40 warm-
up cycles without a failure reported.
• The PCM will cancel the DTC default actions when the
fault no longer exists and the ignition is cycled "off"
long enough to power down the PCM.
Diagnostic Aids
• Charging the battery with a battery charger and jump
starting an engine may set DTC(s). If DTC(s) set when
an accessory is operated, check for faulty connections or
excessive current draw.
• Check for loose/damaged terminals at generator.
• Check belt wear/tension.
• If any engine DTCs are present diagnose and clear these
DTCs first. Then check to see if the transmission DTCs
have set.
Test Description
The numbers below refer to the step numbers on the diagnostic
chart.
3. This test checks charging system voltage.
4. This test checks battery voltage Input at the PCM.
6. This test checks ignition voltage input at the PCM.
FUSE 4B
5 AMP
INTERIOR
C10-J
STATUS
CENTER
POWERTRAIN
CONTROL
MODULE
DLC
2
9-S12-064
5-51
3-1-01