Automatic Transmission Shift Lock Control Function Check - Chevrolet Low Cab Forward 6.7L 2022 Owner's Manual

216 Vehicle Care
Engine:
Removal or rendering engine speed
governor, if so equipped, inoperative so as
to allow engine speed to exceed
manufacturer specifications.
Modification of the engine control system or
calibration.
Fan and Drive:
Removal of fan clutch or rendering clutch
inoperative.
Removal of the fan shroud.
Air Intake:
Removal of air cleaner silencer.
Reversing air cleaner cover.
Exhaust:
Removal of muffler, catalytic converter,
and/or resonator.
Removal of exhaust pipes and exhaust
pipe clamps.
Automatic Transmission Shift Lock
Control Function Check
When Starting Your Vehicle
The selector lever can only be moved from
the "P" position when sufficient brake air
pressure exists and the brake pedal is
pressed. Always firmly press the brake pedal
before attempting to move the selector
lever from "P" to any other position.
When Parking Your Vehicle
The key cannot be removed unless the
selector lever is securely placed in the "P"
position (key interlock system). Be sure to
place the selector lever in the "P" position
when parking the vehicle.
The shift lock system is a system for safety
to prevent incorrect operation of the
automatic transmission model. Use it
correctly and drive safely.
If You Cannot Move the Selector Lever
from the P Position
(Models with ALLISON2550RDS Model
Transmission)
If you cannot move the selector lever from
the "P" position after the engine is started
and the brake air pressure is increased,
follow the section below to perform the
necessary checks.
Caution
When the selector cannot be operated
from the P position to any other position
even after performing the operation
below repeatedly, the shift lock system
may have a failure. Have the vehicle
inspected at your dealer.
Check that you are firmly pressing the brake
pedal. Also, check that the brake air pressure
warning light and buzzer are not operated.
When the brake pedal is not pressed or
there is insufficient brake air pressure to
apply the service brakes, the shift lock
system operates and the selector lever
cannot be shifted from "P" to any other
position.
If your vehicle is parked on a downhill slope,
the push operation of the selector lever may
become heavy to move. In this case, you
can operate the selector lever more
smoothly by pushing the selector lever
toward the front of the vehicle while
pushing the button.
If the selector lever cannot be moved from
"P" to other positions after performing the
instructions given above a number of times,
it is likely that the shift lock function is