GMC Chevy Colorado 2023 Manual page 101

speed to determine Autostart and Autostop conditions.
The ECM also controls the auxiliary coolant pump
motor (if equipped).
Transmission Control Module (TCM)
The TCM monitors the inputs from the transmission
neutral safety switch to determine the driver selected
gear. This information is transmitted to the ECM via
serial data to support the Auto Stop Start algorithm.
Engine Coolant Temperature sensor (ECT)
The ECT sensor is used to determine engine operating
temperature.
Intake Air Temperature Sensor (IAT)
The ECM uses this sensor to monitor ambient air
temperature. If too cold, the Autostop will not occur.
Inside air temperature sensor
The HVAC control module monitors the passenger
compartment temperature sensor to determine the
temperature inside the passenger compartment. The
HVAC control module sends this temperature reading
to the ECM on the data communication circuit. The
ECM uses this temperature values to determine if a
restart is requires based on the temperature inside the
passenger compartment.
Vehicle speed sensor
The vehicle speed sensor is used to determine vehicle
speed. If vehicle speed is detected above a calculated
value during an Autostop condition, the ECM will start
the engine.
Hood Ajar Switch
If the hood switch is in the open position, the vehicle
will not Autostop. If the hood is opened during
Autostop, the vehicle will automatically restart.
Brake Booster Vacuum Sensor
The ECM monitors vacuum in order to ensure proper
power assist for the brake pedal. If the ECM determines
vacuum is too low, it will restart the engine.
Brake Pedal Position Sensor (BPPS) & Accelerator
Pedal Position Sensor (APP)
The ECM monitors both the brake pedal position
sensor and the accelerator pedal position sensor to
determine the level of activation for each. While the
accelerator pedal is in it s at rest position with no
pressure applied by the operator, a partially depressed
Brake pedal will cause the ECM to prepare the engine
for an Autostop event. When the vehicle is in an auto
stop event and the status of the brake pedal position
sensor changes from meeting the autostop criteria to
not meeting this criteria the engine will be restarted
provided all of the other conditions to allow an autostart
are met. If the Accelerator pedal is moved from its at
rest position the vehicle will also enter an auto start
event if all other conditions to support an autostart
event, except for the brake pedal position, are met.
Transmission Gear Shift Position Switch
The transmission gear shift position switch is used to
determine if the transmission is in the proper state to
allow an auto stop/start event. The ECM will not allow
Autostop until the brake is engaged, the transmission is
2023 - Colorado Electrical Body Builder Manual
12 V Starting and Charging
in the forward gear position and then the vehicle slows
to below the minimum speed required to allow and
autostop while meeting all of the other minimum criteria
to support an autostop event.
Coolant Pump Motor
The ECM will turn on the auxiliary coolant pump motor
during Autostop to maintain engine operating
temperature and HVAC temperature. Once the engine
is running, the ECM will turn off the coolant pump
motor.
Body Control Module (BCM)
The Body Control Module (BCM) monitors the Autostop
Disable switch in order to enable or disable the system.
It sends the appropriate messages to the ECM Via
serial data to enable or disable the system.
Battery Sensor Module
The Battery Sensor Module monitors the battery current
load, state of health, and state of charge, the
information is sent to the BCM Via LIN then to the ECM
Via Serial Data. If the module detects high current load,
the battery is in a poor state of health or a low charge
condition, the ECM will not allow Autostop to occur.
Autostop Disable Switch
The disable switch is an input to the BCM, it allows the
customer to disable or re-enable the Autostop system.
After the vehicle is turned off the Autostop system will
turn back on the next time the vehicle is started.
Power Supply Transformer
The DC to DC converter monitors battery voltage and
will maintain operating voltage to the radio, instrument
cluster and instrument panel displays. The DC to DC
converter will provide a boosted voltage to sensitive
loads during Autostart to ensure proper operation of the
driver informational displays.
Instrument Cluster
In order to differentiate between a normal engine shut
down (engine speed 0 RPM) and when the engine has
been shut down by the Stop/Start System, the
tachometer needle will rest at the Autostop indicator
icon (500 RPM point) indicating the engine has been
shut down by the Stop/Start System. Once the engine
is restarted, or the ECO button has disengaged
Autostop, the tachometer will function normally.
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