Electronic Park Lock (EPL)/Ignition Lock Cylinder Control Actuator
If the vehicle is equipped with automatic transmission and a floor mounted console gear
shift, it has an ignition lock cylinder control actuator system in the steering column. The
ignition lock cylinder control actuator purpose is to prevent the ignition key from being
turned to the OFF position when the transmission is in any position other than PARK and
the vehicle may still be moving. The column ignition lock system consists of an ignition lock
cylinder control actuator and a park position switch that is located in the automatic
transmission shift lock control switch. The ignition lock cylinder control actuator contains a
pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned
to the lock position when the vehicle transmission is not in the PARK position. If vehicle
power is lost, and/or the transmission is not in the PARK position the operator will not be
able to turn the ignition key to the lock position and will not be able to remove the ignition
key from the column.
Linear Shift Assembly
If the vehicle is equipped with a column mounted gear shift, it has a linear shift assembly on
the steering column. The linear shift assembly has a cable that runs from the linear shift
assembly to the ignition lock cylinder case. The purpose of this cable is to prevent the
ignition key from being turned to the OFF position when the transmission is in gear and the
vehicle may still be moving. The linear shift assembly cable contains a pin that is spring
loaded to mechanically prevent the ignition key cylinder from being turned to the lock
position when the vehicle transmission is not in the PARK position. If vehicle power is lost,
and/or the transmission is not in the PARK position the operator will not be able to turn the
ignition key to the lock position and will not be able to remove the ignition key from the
column.
SIR Coil and Module
For additional information on the operation of the SIR coil and module, refer to SIR
System Description and Operation .
Automatic Transmission Shift Lock Actuator
The automatic transmission shift lock control system is a safety device that prevents an
inadvertent shift out of PARK when the engine is running. The driver must press the brake
pedal before moving the shift lever out of the PARK position. The system consists of the
following components: the automatic transmission shift lock control solenoid, the automatic
transmission shift lock control switch, the body control module (BCM), the powertrain
control module (PCM)/engine control module (ECM). With the ignition in the ON position,
2007 Hummer H3
2007 STEERING Steering Wheel and Column - H3