spark plugs.

5501230

5501227

Engine Block
The aluminum alloy engine cylinder block is made by
high pressure die casting with three cast-in-place iron
cylinder liners. Of the four crankshaft bearings, the
thrust bearing is located on the third bearing from the
front of the engine. A lower structural extension forms
the lower portion of the crankcase to promote cylinder
block rigidity and reduce engine noise and vibration.

Balance Shaft Assembly
The balance shaft is gear driven off the crankshaft at
the front of the engine. The balance shaft drive the oil
pump using a belt.
Crankshaft
The crankshaft is made of forged micro alloy steel. Four
counterweights provide precision engine balance. A
harmonic balancer controls torsional vibration.
The crankshaft is offset from the cylinder centerline to
help reduce resistance between the piston and the
cylinder during the combustion stroke. This improves
fuel economy.
Pistons and Connecting Rods
The cast aluminum pistons are a lightweight and
low-friction design with a recessed top and a
barrel-shaped, graphite-coated skirt. The pistons use
two compression rings and one oil control ring
assembly. The chromium steel pins are designed to be
full-floating and must be serviced with the pistons as an
assembly. The powdered metal connecting rods are
fractured at the connecting rod journal and machined
for proper clearance.
Oil Cooler
The oil cooler heat exchanger is mounted to the lower
left side of the engine, on the coolant pump housing,
and is used to cool the engine oil.

5501229

Cylinder Head
The cylinder head is a dual overhead camshaft design
made of cast aluminum alloy. Its combustion chamber
contains four valves per cylinder and is designed for
increased swirl efficiency of the incoming air charge to

Camshafts
The engine has two camshafts, one for the intake
valves and another one for the exhaust valves. The
camshafts are driven using a Belt-in-Oil system. This
system reduces noise and friction compared to timing
chains and dry belt systems. Both the timing belt and
the oil drive belt have a change interval of 240,000 km
(150,000 miles) or 15 years.

Page 8

February, 2020

Timing Belt System
The camshaft actuator system on 1.2L (LIH) engine is
much like the camshaft actuator systems found on
other GM engines. This system enables the engine
control module to change camshaft timing while the
engine is running. The intake and exhaust camshaft
position actuator assemblies vary the camshaft position
in response to directional changes in oil pressure.
Camshaft Position Sensors
There are two camshaft position sensors on the
camshafts and are used by the ECM to detect which
cylinder is on the compression stroke and control the
camshaft actuator system. A malfunction in a camshaft
position sensor will cause the ECM to command the
camshaft actuators to a parked position and may cause
a longer than normal crank time.
Evaporative Emission Purge Pump
The 1.2L (LIH) engine is equipped with an evaporative
emission purge pump located on the left front of the
engine. This pump is necessary because the purge
capacity is reduced by technologies that improve fuel
economy. The purge pump is required to increase the
purge volumes to meet Low Emission Vehicle 3
Evaporative Emission requirements. This pump has an
integral pressure sensor and is controlled by the engine
control module.

Bulletin No.: 20-NA-032

The refrigerant system consists of the following
components:
• Compressor
• Condenser
• Receiver/Dehydrator
• Thermostatic Expansion Valve
• Evaporator Core
• Refrigerant Lines
• High and Low Side Charge Ports
The vehicle Air Conditioning (A/C) system uses R-134a
or R1234yf refrigerant and a fixed displacement,
cycling clutch compressor.
Within the refrigerant system, refrigerant travels from
the compressor to the condenser. The cooling fan cools
the refrigerant. The condenser contains a receiver/
dehydrator within the left side of the condenser. In this
system, the refrigerant filter or desiccant element within
the receiver/dehydrator is serviced separately from the
condenser assembly.

HVAC

5501232

5501234

Heating and A/C Overview
The climate control system regulates the temperature
inside the vehicle cabin. The vehicle uses a dual zone
automatic climate control system that can operate
either manually or automatically. Depending on region
and optional content, the climate control system
provides heat only or both heat and air conditioning.
The Heating, Ventilation, and Air Conditioning (HVAC)
system may also incorporate an air filtration feature.

A/C Operation and Compressor Control
To operate the A/C system, the driver presses the A/C
request switch located on the HVAC control faceplate.
The HVAC control faceplate sends a message to the
HVAC control module over a dedicated Local
Interconnect Network (LIN). The HVAC module then
relays the signal over the General Motors Local Area
Network (GMLAN) to the Engine Control Module (ECM)
to request A/C compressor operation.
When the ECM receives an A/C ON request, the ECM
monitors the refrigerant pressure sensor, throttle
position sensor, Engine Coolant Temperature (ECT)
sensor, and engine speed. If all operating criteria are
within preset limits, the ECM engages the compressor
clutch by providing ground to the A/C clutch relay. The
ECM cycles the compressor on and off, depending
upon the refrigerant pressure sensor readings.

Bulletin No.: 20-NA-032

February, 2020

The following conditions must be met in order to
activate the A/C compressor:
– Battery voltage is between 9–18 V
– Engine coolant temperature is less than 120°C
(248°F)
– Engine speed is greater than 600 RPM
– Engine speed is less than 6200 RPM
– A/C high side pressure is between 220-3100 kPa
(32-450 PSI)
– Throttle position is less than 95%
– Evaporator temperature is greater than 3°C (38°F)
– ECM does not detect an excessive torque load
– ECM does not detect insufficient idle quality
– Outside air temperature is greater than 3°C (38°F)
– Blower motor ON
The HVAC control module uses the evaporator
temperature sensor to monitor the evaporator
temperature when the A/C system is operating. If the
HVAC control module detects that the evaporator
temperature is less than 3°C (38°F), the A/C
compressor is turned off to prevent the evaporator from
freezing.

Page 9

The windshield moisture and temperature sensor
measures the relative humidity on the passenger
compartment side of the windshield. Warm, humid air
traveling across a cool windshield could allow the water
in the air to condense and collect on the inside of the
windshield as fog. By measuring in-car humidity, air
temperature, and windshield temperature, the HVAC
control module can proactively engage the A/C and
send drier, less humid air across the windshield to
prevent fog from forming. This action automatically
defogs the windshield.
The windshield moisture and temperature sensor is in
an optimal location at the base of the inside rearview
mirror. This location ensures that it is placed in the
airstream produced by the windshield defroster vents.
The windshield moisture and temperature sensor
includes the relative humidity sensor, humidity sensing
element temperature sensor, and windshield
temperature sensor.
The moisture sensor is a plate capacitor that changes
its ability to store an electric charge in proportion to the
amount of moisture in the surrounding air. The moisture
sensor contains conductive plates separated by
dielectric plates. The dielectric plates are made of a
material that changes its electrical properties in the
presence of moisture. The change in electrical
properties changes the ratio of the charge of the
capacitor. The humidity sensor electronics change the
capacitance measured across the capacitor to a
voltage signal that is proportional to humidity.

Body Systems
Overview
The 2020 Buick Encore GX body systems include
many premium features. This section covers the
exterior lighting, steering wheel controls, hands-free
power liftgate, adaptive cruise control, power windows,
wireless charging, 110-volt power outlets, power seats,
power sunroof, rear camera washer, and moisture
sensitive windshield wipers.

5501233

Temperature Sensors
Automatic HVAC control systems use several
temperature sensors:
– inside air temperature sensor
– left and right upper outlet duct air temperature sensor
– left and right lower outlet duct air temperature sensor
– windshield moisture and temperature sensor
The sensors monitor the temperature in the ducts and
is used by the HVAC control module to adjust the
delivery temperature from the duct.

Exterior Lighting
The 2020 Encore GX includes either halogen
headlamps or brighter Light Emitting Diode (LED)
headlamps, LED daytime running lamps, and fog
lamps.

Page 10

February, 2020

Bulletin No.: 20-NA-032

Power Seats
The front power seats system consist of the following
components:
– Seat Adjuster Switch
– Seat Horizontal Motor
– Seat Front Vertical Motor (If equipped)
– Seat Rear Vertical Motor
– Seat Recline Motor

5501116

1. Low/High Beams
2. Turn/Park Lamps
3. Fog Lamps
The standard rear tail lamps use incandescent bulbs,
while the center high-mounted stop lamp, license plate,
and backup lamps uses LED bulbs. The up-level
models incorporate tail lamp LED technology.
Interior Systems
Manual Seat Adjuster
To adjust the forward and backward movement of a
manual seat:

5501236

1. Pull the handle at the front of the seat.
2. Slide the seat to the desired position and release
the handle.
3. Try to move the seat back and forth to be sure its
locked in place.

5501238

If equipped with memory seats, the following additional
components are included:
• Seat Memory Control Module
• Seat Memory Switch
Memory seats allow the seat to return to a learned
position. This may be set to be either a supervised/
manual operation or linked to the keyfob and performed
automatically when the vehicle is started.
Auto memory and seat exit may be turned on in the
vehicle settings. When enabled, an auto memory
position may be learned for RKE transmitters 1 or 2;
transmitters 3–8 may not be used for this feature.
40/60 Split-Folding Rear Seat
All 2020 Buck Encore GX models include a standard
40/60 split-folding rear seat. The larger, 60% portion of
the seat is located on the passenger side of the vehicle.
The feature provides a larger cargo load area on the
folded passenger side seat and still maintains the
provision for a rear-seating passenger on the
driver’s side.
Power Door Locks
The Buick Encore GX is equipped with power door
locks. The power door locks are controlled by the BCM.
The BCM provides a power door lock command to the
door lock actuators within the door latches whenever it
receives an input signal from one of the following
sources:
• power door lock switches (located on the driver
and passenger doors)
• keyless entry lock or unlock command

Bulletin No.: 20-NA-032

February, 2020

• passive keyless entry
• door lock cylinder switch unlock actuation
• delayed locking command
• automatic door lock command
The door locks also feature lockout prevention, which
prevents the doors from locking if the transmitter is in
the vehicle.
The doors may be unlocked using the power door lock
switches, the unlock button on the keyless entry
transmitter, or by approaching the vehicle with the
passive keyless entry transmitter and pressing the
button on the door handle. Low frequency transmitting
antennas located in the front door handles and the
liftgate send a challenge to the key fob to determine if it
is within the 1 meter range to allow the vehicle to
unlock.
The doors may be manually unlocked from inside the
vehicle by pulling on the inside door handle. The first
pull of the handle unlocks the door and the second pull
of the door handle opens the door.

•
•

Page 11

metallic foreign objects are detected on the
charging pad
the charger temperature exceeds 85°C (185°F)

5501240

110V/120V Power Outlet Receptacles
The accessory DC/AC power inverter module converts
12V DC battery power to 100–120 volts of AC power.
The accessory DC/AC power inverter module provides
up to 150 watts of power. The power outlet is located at
the rear of the center console.
The power outlet receptacle incorporates an indicator
light, which illuminates when it is in use. The light
illuminates when the ignition is on, equipment requiring
less than 150 watts is plugged into the outlet, and
system faults are not detected. The accessory DC/AC
power inverter module also features a protection circuit
that turns OFF power to the receptacle when a device
draws more than 150 watts of power. To reset the
circuit, remove the plug and connect the plug or turn the
retained accessory power off and then back on.
5501239

Mobile Device Wireless Charging
The mobile device wireless charging system detects
and establishes communications with the mobile device
to confirm its compatibility and delivers charging power
via a wireless interface. The wireless charging system
is able to deliver up to 15 watts of power.
The wireless charger incorporates a charging coil
located in the center of the charging surface. The
mobile device also has a charging coil, typically near
the center of the device. In order for the charging
process to proceed, place the mobile device on the
charging pad and line up both coils.
The wireless charging system does not enter a
charging state if any of the following conditions occurs:
• communication is not established with a
compatible device
• a non-compatible device is detected

Power Liftgate
The power liftgate is equipped on some models, and its
system consists of the following components:
– Liftgate Control Module
– Liftgate Position Sensor (Part of the power assist
actuator)
– Interior Liftgate Rotary Switch
– Liftgate Handle Switch
– Liftgate Power Assist Actuator
– Liftgate Latch Assembly
– Liftgate Switches/Operation
– Object Detection Sensors (Pinch Guards)
– Hands Free Liftgate Hands Free Sensor Control
Module
– Keyless Entry Transmitter
– Remote Control Door Lock Receiver
– Upper and Lower Liftgate Hands Free Sensors

Page 12

February, 2020

The power liftgate is operated by pressing the power
liftgate switch, using the hands-free sensor, or by
pressing the liftgate button on the keyless entry
transmitter (key fob.) The following steps allow the
liftgate to open:
1. The switch contacts close.
2. The signal circuit voltage goes low.
3. The liftgate control module determines if conditions
are met for power liftgate operation.
Alternatively, the liftgate may be manually operated by
pressing the liftgate latch release button, located on the
exterior of the liftgate.

Bulletin No.: 20-NA-032

Optional Sunroof Features
The power sunroof and sunshade system consists of a
moving glass panel and a second stationary panel for
rear skylight behind the moving panel. There is also an
optional power sunroof sunshade, which covers both
glass panels. The front panel tilts to the vent position or
can fully open with one-touch power express-open and
express-close switches located in the overhead
console.
The power sunroof system operates only with the
ignition turned to the RUN or ACCESSORY position.
This allows for retained accessory power control of the
sunroof and sunshade through the BCM. When the
ignition switch is turned to off, the sunroof and
sunshade will continue to operate until any door is
opened or when the retained accessory power
times out.

Driveline/Axle
Overview
The driveline in the 2020 Buick Encore GX uses either
a Front-Wheel Drive (FWD) or an All-Wheel Drive
(AWD) configuration. Both configurations use a
transverse mounted engine and transmission to
transfer power through the front wheel driveshafts to
the front wheels. The AWD configuration adds an active
transfer case after the transmission that splits the
power between the two-piece rear propeller shaft and
the front wheel driveshafts.

5501118

Some vehicles come equipped with hands-free liftgate
operation. This system uses a motion sensor located
under the left rear bumper fascia, and if equipped, an
optional logo projector. Waving your foot under the
sensor area near the projected logo will cause the
liftgate to open.

5501120

Transfer Case
The AWD 2020 Buick Encore GX features a one-speed
transfer case. The transfer case bolts to an adapter
plate on the right side of the transmission. The housing,
bearings, and gears are not serviceable. Internal
damage to the unit requires replacement of the
assembly.

5501242

Bulletin No.: 20-NA-032

February, 2020

Propeller Shafts
The propeller shaft is tubular-shaped with Constant
Velocity (CV) joints at both ends, and transmits power
from the transfer case output shaft to the rear
differential.
A center bearing assembly in the rear propeller shaft
supports the propeller shaft connection point and helps
isolate the vehicle from vibration. A CV joint connects
the two pieces.
Differentials
The AWD system has a driver-selectable disconnect
and has a single-clutch rear drive unit. The rear drive
unit design allows for independent and balanced torque
distribution between the front and rear wheels in an up
to 50-50 split under certain driving conditions. The rear
drive axle has an extended torque tube that allows a
shorter 2-piece driveshaft.
Wheel Driveshafts
The wheel driveshaft inner joints use a tripod CV-joints
design. This type of joint allows a large range of
working angles with inward and outward movement to
compensate for ride height changes caused by normal
vehicle suspension movement.
CV joints at the outer ends of the driveshafts are
Rzeppa-style joints designed to permit larger working
angles. All of the joints are covered with thermoplastic
boots with stainless steel clamps that retain joint
lubricating grease and prevent dirt and debris from
entering the joint, causing accelerated wear.

Page 13

Hydra-Matic 9T45 (M3F) Automatic Transmission
The Hydra-Matic 9T45 is a fully automatic, 9-speed,
transverse-mounted, electronic-controlled
transmission. It consists primarily of a 4-element torque
converter, a compound planetary gear set, friction and
mechanical clutch assemblies, and a hydraulic
pressurization and control system.
The planetary gear sets provide the nine forward gear
ratios and reverse. Changing gear ratios is fully
automatic and is accomplished with a Transmission
Control Module (TCM).
Selectable One-Way Clutch
The selectable 1 way clutch is part of the 1-reverse and
1-2-3-4-5-6 clutch housing. The selectable one-way
clutch has two modes of operation. In the released
mode, it will hold in one direction and free-wheel in the
other direction. In the applied mode, it holds in both
directions.