Hummer H1 Service Manual page 266

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DTC P0719 Brake Switch Circuit - Low Input,
Stuck "ON"
Circuit Description
The brake switch indicates brake pedal position. The normally-
closed brake switch supplies a B+ signal on circuit 810 to the
PCM. The signal voltage circuit is opened when the brakes are
applied. The PCM uses this signal to deenergize the converter
clutch solenoid when the brakes are applied.
This DTC detects an open brake switch during acceleration.
Conditions For Setting The DTC
• No DTC P0502.
• The PCM detects an open brake switch/circuit (0 volts)
for 15 minutes without going off for 2 seconds, and the
following events occur seven consecutive times: vehicle
speed is less than 8 km/h (5 mph); then vehicle speed is
between 8 and 32 km/h (5 and 20 mph) for 4 seconds;
then vehicle speed is greater than 32 km/h (20 mph) for
6 seconds.
Action Taken When The DTC Sets
• The PCM will NOT illuminate the warning lamp.
• PCM will disregard the brake switch state if TP is more
than 12% and vehicle speed is greater than 40 mph.
05745159
FUSE 2D
20 AMP
INTERIOR
C28-D13 C28-C13 C28-C12 C28-C11
BATTERY IGNITION
POSITIVE VOLTAGE
Transmission/Transfer Case
FUSE 3A FUSE 4D
20 AMP 15 AMP
EXTERIOR INTERIOR
A
BRAKE
LAMP CRUISE
B
31
C1-
TO BRAKE
LAMP
C29-B10 C29-B9
BRAKE LIGHT
SWITCH SIGNAL BRAKE SWITCH
POWERTRAIN
CONTROL
MODULE (PCM)
Conditions For Clearing DTC
• The PCM will turn off the warning lamp after three con-
secutive ignition cycles without a failure reported.
• The DTC can be cleared from PCM memory by using a
scan tool. It 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.
FUSE 6B
5 AMP
INTERIOR
D
TCC/
C
40
TCC / CRUISE
9-S12-069
5-67