2019 INFINITI Q50 Engine control

5-128Starting and driving
moves.
4. Push the ignition switch to the OFF position.ELECTRIC POWER STEERING
TYPE
WARNING
.If the engine is not running or is
turned off while driving, the power
assist for the steering will not work.
Steering will be harder to operate.
. When the power steering warning
light illuminates with the engine run-
ning, the power assist for the steer-
ing will cease operation. You will still
have control of the vehicle but the
steering will be harder to operate.
The electric power steering is designed to
provide power assist while driving to oper-
ate the steering wheel with light force.
When the steering wheel is operated re-
peatedly or continuously while parking or
driving at a very low speed, the power assist
for the steering wheel will be reduced. This is
to prevent overheating of the electric power
steering and protect it from getting da-
maged. While the power assist is reduced,
steering wheel operation will become heavy.
When the temperature of the electric power
steering goes down, the power assist level
will return to normal. Avoid repeating such steering wheel operations that could cause
the electric power steering to overheat.
You may hear a sound when the steering
wheel is operated quickly. However, this is
not a malfunction.
If the power steering warning light illumi-
nates while the engine is running, it may
indicate the electric power steering is not
functioning properly and may need servicing.
It is recommended you have the electric
power steering checked by an INFINITI
retailer. (See “Power steering warning light”
(P.2-14).)
When the power steering warning light
illuminates with the engine running, the
power assist for the steering will cease
operation. You will still have control of the
vehicle. However, greater steering effort is
needed, especially in sharp turns and at low
speeds.
HYDRAULIC PUMP ELECTRIC
POWER STEERING TYPE
WARNING
When the power steering warning light
illuminates with the engine running, the
power assist for the steering will cease
operation. You will still have control of
POWER STEERING

the vehicle, but the steering will be much
harder to operate.
The hydraulic pump electric power steering
is designed to provide power assistance
while driving to operate the steering wheel
with light force.
When the steering wheel is operated re-
peatedly or continuously while parking or
driving at a very low speed, the power assist
for the steering wheel will be reduced. This is
to prevent overheating of the hydraulic
pump electric power steering and protect it
from getting damaged. While the power
assist is reduced, steering wheel operation
will become heavy. If the steering wheel
operation is still performed, the power
steering may stop and the power steering
warning light will illuminate. Stop the engine
and place the ignition switch in the OFF
position. The temperature of the hydraulic
pump electric power steering will go down
and the power assist level will return to
normal after starting the engine. The power
steering warning light will go off. Avoid
repeating such steering wheel operations
that could cause the hydraulic pump electric
power steering to overheat.
You may hear a noise from the front of the
vehicle when the steering wheel is operated.
This is not a malfunction. If the power steering warning light illumi-
nates while the engine is running, it may
indicate the hydraulic pump electric power
steering is not functioning properly and may
need servicing. It is recommended you have
the hydraulic pump electric power steering
checked by an INFINITI retailer.
When the power steering warning light
illuminates with the engine running, the
power assist for the steering will cease
operation but you will still have control of
the vehicle. At this time, greater steering
efforts are required to operate the steering
wheel, especially in sharp turns and at low
speeds.
DIRECT ADAPTIVE STEERING
TYPE
WARNING
.
When the power steering warning
light illuminates with the engine run-
ning, the power assist for the steer-
ing will cease operation. You will still
have control of the vehicle, but the
steering will be harder to operate.
. If wheels or tires other than the
INFINITI recommended ones are
used, Direct Adaptive Steering may
not operate properly and the power steering warning light may illumi-
nate.
. Do not modify the vehicle’s suspen-
sion. If suspension parts such as
shock absorbers, struts, springs, sta-
bilizer bars, bushings and wheels are
not INFINITI recommended for your
vehicle or are extremely deteriorated,
Direct Adaptive Steering may not
operate properly and the power
steering warning light may illumi-
nate.
. Do not modify the vehicle’s steering.
If steering parts are not INFINITI
recommended for your vehicle or are
extremely deteriorated, Direct Adap-
tive Steering may not operate prop-
erly and the power steering warning
light may illuminate.
. If the VDC warning light illuminates,
the power steering warning light may
also illuminate at the same time. Stop
the vehicle in a safe location, turn the
engine off and restart the engine. If
the power steering warning light
continues to illuminate, have the
system checked. It is recommended
you visit an INFINITI retailer for this
service. For VDC system, see “Vehicle
Dynamic Control (VDC) system”
(P.5-133).
Starting and driving5-129

5-130Starting and driving
CAUTION
.Do not place the ignition switch is in
the ON position while the steering
wheel or a tire is removed.
. Do not turn the steering wheel as
much as possible while the ignition
switch is in any position other than
the ON position.
. Installing an accessory on the steer-
ing wheel, or changing the steering
wheel, may reduce the steering per-
formance.
Direct Adaptive Steering is designed to
control the steering force and steering angle
according to the vehicle speed and amount
of turning of the steering wheel.
The steering characteristic can be selected
using the INFINITI Drive Mode Selector. See
“INFINITI Drive Mode Selector” (P.5-22).
If the VDC system is turned off, the setting
of steering becomes standard mode.
If the power steering warning light illumi-
nates while the engine is running, it may
indicate that Direct Adaptive Steering is not
functioning properly and may need servicing.
It is recommended you have the system
checked by an INFINITI retailer. (See “Power steering warning light” (P.2-14).)
When the power steering warning light
illuminates with the engine running, the
power assist for the steering will cease
operation. You will still have control of the
vehicle. However, greater steering effort will
be needed, especially in sharp turns and at
low speeds.
If Direct Adaptive Steering is malfunction-
ing, the steering wheel may turn slightly even
when driving on a straight road.
Under the following conditions, the steering
wheel may turn slightly even when driving on
a straight road. This is due to a protection
mechanism for Direct Adaptive Steering. The
steering wheel will return to the normal
position after the protection mechanism is
deactivated.
Condition A
.
When the engine is stalled or likely to be
stalled
. When the steering wheel is held in the full
lock position or when the front tire
touches an obstruction.
. When the battery is discharged
To return the steering wheel to the normal
position, stop the vehicle in a safe location
and stop operating the steering wheel. Then
drive the vehicle for a short period of time. Condition B
.
When the steering wheel is operated
repeatedly or continuously while parking
or driving at a very low speed. In this
case, the power assist for the steering
wheel will be reduced.
To return the steering wheel to the normal
position, stop the vehicle in a safe location
and wait for a period of time, without
operating the steering wheel, until the
temperature of Direct Adaptive Steering
cools down. Avoid repeated steering wheel
operations that could cause Direct Adaptive
Steering to overheat.
When the vehicle is tested on the 2-wheel
dynamometer, the power steering warning
light may illuminate. To turn off the power
steering warning light, stop the vehicle in a
safe location, turn the engine off, restart the
engine, and then drive the vehicle for a
period of time.
The following conditions do not indicate a
malfunction of Direct Adaptive Steering.
. You may notice wider steering play when
the ignition switch is in the OFF or ACC
position compared to when it is in the
ON position.
. After the engine is started, the steering
wheel may turn slightly even when
driving on a straight road. To return to
the normal position, drive the vehicle on

a straight road for a period of time.
. After the engine is started, the steering
wheel may move if the steering wheel
was turned to the fully locked position
while the ignition switch was in the OFF
position.
. After the vehicle is tested on the 4-wheel
dynamometer, the steering wheel may
turn slightly even when driving on a
straight road. To return the steering
wheel to the normal position, drive the
vehicle on a straight road for a period of
time.
You may hear a noise under the following
conditions. However, this is not a malfunc-
tion.
. When the engine is started or stopped.
. When the steering wheel is turned in the
full lock position.BRAKING PRECAUTIONS
The brake system has two separate hydrau-
lic circuits. If one circuit malfunctions, you
will still have braking at two wheels.
Vacuum assisted brakes
The brake booster aids braking by using
engine vacuum. If the engine stops, you can
stop the vehicle by depressing the brake
pedal. However, greater foot pressure on
the brake pedal will be required to stop the
vehicle and the stopping distance will be
longer.
Using the brakes
Avoid resting your foot on the brake pedal
while driving. This will cause overheating of
the brakes, wearing out the brake and pads
faster and reduce gas mileage.
To help save the brakes and to prevent the
brakes from overheating, reduce speed and
downshift to a lower gear before going
down a slope or long grade. Overheated
brakes may reduce braking performance and
could result in loss of vehicle control.
WARNING
. While driving on a slippery surface,
be careful when braking, accelerating or downshifting. Abrupt braking or
accelerating could cause the wheels
to skid and result in an accident.
. If the engine is not running or is
turned off while driving, the power
assist for the brakes will not work.
Braking will be harder.
Wet brakes
When the vehicle is washed or driven
through water, the brakes may get wet. As
a result, your braking distance will be longer
and the vehicle may pull to one side during
braking.
To dry brakes, drive the vehicle at a safe
speed while lightly tapping the brake pedal
to heat-up the brakes. Do this until the
brakes return to normal. Avoid driving the
vehicle at high speeds until the brakes
function correctly.
PARKING BRAKE BREAK-IN
Break in the parking brake shoes whenever
the stopping effect of the parking brake is
weakened or whenever the parking brake
shoes and/or drums/rotors are replaced, in
order to assure the best braking perfor-
mance.
This procedure is described in the vehicle
service manual. It is recommended you visit
Starting and driving5-131
BRAKE SYSTEM

wheel from locking, the system helps the
driver maintain steering control and helps to
minimize swerving and spinning on slippery
surfaces.
Using the system
Depress the brake pedal and hold it down.
Depress the brake pedal with firm steady
pressure, but do not pump the brakes. The
ABS will operate to prevent the wheels from
locking up. Steer the vehicle to avoid
obstacles.
WARNING
Do not pump the brake pedal. Doing so
may result in increased stopping dis-
tances.
Self-test feature
The ABS includes electronic sensors, electric
pumps, hydraulic solenoids and a computer.
The computer has a built-in diagnostic
feature that tests the system each time you
start the engine and move the vehicle at a
low speed in forward or reverse. When the
self-test occurs, you may hear a “clunk”
noise and/or feel a pulsation in the brake
pedal. This is normal and does not indicate a
malfunction. If the computer senses a mal-function, it switches the ABS off and
illuminates the ABS warning light on the
instrument panel. The brake system then
operates normally, but without anti-lock
assistance.
If the ABS warning light illuminates during
the self-test or while driving, have the
vehicle checked. It is recommended you visit
an INFINITI retailer for this service.
Normal operation
The ABS operates at speeds above 3 to 6
MPH (5 to 10 km/h).
When the ABS senses that one or more
wheels are close to locking up, the actuator
rapidly applies and releases hydraulic pres-
sure. This action is similar to pumping the
brakes very quickly. You may feel a pulsation
in the brake pedal and hear a noise from
under the hood or feel a vibration from the
actuator when it is operating. This is normal
and indicates that the ABS is operating
properly. However, the pulsation may indi-
cate that road conditions are hazardous and
extra care is required while driving.
The Vehicle Dynamic Control (VDC) system
uses various sensors to monitor driver inputs
and vehicle motion. Under certain driving
conditions, the VDC system helps to perform
the following functions.
.
Controls brake pressure to reduce wheel
slip on one slipping drive wheel so power
is transferred to a non slipping drive
wheel on the same axle.
. Controls brake pressure and engine out-
put to reduce drive wheel slip based on
vehicle speed (traction control function).
. Controls brake pressure at individual
wheels and engine output to help the
driver maintain control of the vehicle in
the following conditions:
— understeer (vehicle tends to not follow the steered path despite increased
steering input)
— oversteer (vehicle tends to spin due to certain road or driving conditions).
The VDC system can help the driver to
maintain control of the vehicle, but it cannot
prevent loss of vehicle control in all driving
situations.
When the VDC system operates, the VDC
warning light
in the instrument panel
flashes so note the following:
. The road may be slippery or the system
may determine some action is required to
help keep the vehicle on the steered path.
Starting and driving5-133
VEHICLE DYNAMIC CONTROL
(VDC) SYSTEM

5-134Starting and driving
.You may feel a pulsation in the brake
pedal and hear a noise or vibration from
under the hood. This is normal and
indicates that the VDC system is working
properly.
. Adjust your speed and driving to the road
conditions.
See “Vehicle Dynamic Control (VDC) warn-
ing light” (P.2-15).
If a malfunction occurs in the system, the
VDC warning light
illuminates in the
instrument panel. The VDC system automa-
tically turns off.
The VDC OFF switch is used to turn off the
VDC system. The VDC off indicator light
illuminates to indicate the VDC system is off.
When the VDC switch is used to turn off the
system, the VDC system still operates to
prevent one drive wheel from slipping by
transferring power to a non slipping drive
wheel. The VDC warning light
flashes if
this occurs. All other VDC functions are off,
except for brake force distribution, and the
VDC warning light
will not flash. The
VDC system is automatically reset to on
when the ignition switch is placed in the off
position then back to the on position.
See “Vehicle Dynamic Control (VDC) warn-
ing light” (P.2-15) and “Vehicle Dynamic
Control (VDC) off indicator light” (P.2-18).
The computer has a built-in diagnostic feature that tests the system each time you
start the engine and move the vehicle
forward or in reverse at a slow speed. When
the self-test occurs, you may hear a “clunk”
noise and/or feel a pulsation in the brake
pedal. This is normal and is not an indication
of a malfunction.
VDC operation is reduced when the INFINITI
Drive Mode Selector is used to select the
SPORT+ mode (if so equipped). The VDC
system may not operate in the same circum-
stances when compared to operation in the
standard mode. To help prevent accidents
drive carefully, avoid careless or dangerous
driving techniques and be especially careful
when driving and cornering on slippery
surfaces.
BRAKE FORCE DISTRIBUTION
During braking while driving through turns,
the system optimizes the distribution of
force to each of the four wheels depending
on the radius of the turn.
WARNING
.
The VDC system is designed to help
the driver maintain stability but does
not prevent accidents due to abrupt
steering operation at high speeds or
by careless or dangerous driving techniques. Reduce vehicle speed
and be especially careful when driving
and cornering on slippery surfaces
and always drive carefully.
. The brake force distribution system
may not be effective depending on
the driving condition. Always drive
carefully and attentively.
. Do not modify the vehicle’s suspen-
sion. If suspension parts such as
shock absorbers, struts, springs, sta-
bilizer bars, bushings and wheels are
not INFINITI recommended for your
vehicle or are extremely deteriorated,
the VDC system may not operate
properly. This could adversely affect
vehicle handling performance, and
the VDC warning light
may
illuminate.
. If brake related parts such as brake
pads, rotors and calipers are not
INFINITI recommended or are extre-
mely deteriorated, the VDC system
may not operate properly and the
VDC warning light
may illumi-
nate.
. If engine control related parts are not
INFINITI recommended or are extre-
mely deteriorated, the VDC warning
light
may illuminate.

.When driving on extremely inclined
surfaces such as higher banked cor-
ners, the VDC system may not oper-
ate properly and the VDC warning
light
may illuminate. Do not drive
on these types of roads.
. When driving on an unstable surface
such as a turntable, ferry, elevator or
ramp, the VDC warning light
may
illuminate. This is not a malfunction.
Restart the engine after driving onto
a stable surface.
. If wheels or tires other than the
INFINITI recommended ones are
used, the VDC system may not oper-
ate properly and the VDC warning
light
may illuminate.
. The VDC system is not a substitute
for winter tires or tire chains on a
snow covered road. This system senses driving based on the
driver’s steering and acceleration/braking
patterns, and controls brake pressure at
individual wheels to help smooth vehicle
response.
When the SPORT mode is selected by the
INFINITI Drive Mode Selector, the amount
of brake control provided by the active trace
control is reduced.
When the PERSONAL mode is selected, the
active trace control can be set to ON
(enabled) or OFF (disabled). See “INFINITI
Drive Mode Selector” (P.5-22).
When the VDC OFF switch is used to turn
off the VDC system, the active trace control
is also turned off.
Starting and driving5-135
ACTIVE TRACE CONTROL

5-138Starting and driving
The Idling Stop System activates to prevent
unnecessary fuel consumption, exhaust
emissions and noise.
.When you fully depress the brake pedal
to stop the vehicle, the engine is turned
off automatically.
. When you release the brake pedal to
begin moving again, the engine is turned
on automatically.
WARNING
The engine restarts if the vehicle moves
at approximately 1 MPH (2 km/h) or
more (on a downhill grade, etc.), while
the engine is turned off by the Idling
Stop System. Depress the brake pedal
immediately to stop the vehicle to pre-
vent an accident.
CAUTION
At the end of the journey the engine
must be stopped and ignition switch be
turned off. Lock the vehicle as normal.
Turning the ignition switch OFF will shut
down all electrical systems. Failure to do
this may result in a discharged battery. NOTE:
The Idling Stop System will not activate
under the following conditions:
.
when the engine is kept idling without
the vehicle being driven after the engine
is turned on.
. when the engine coolant temperature is
low.
. when the battery capacity is low.
. when the battery temperature is low or
extremely high.
. when the vehicle is moving.
. when a negative pressure booster de-
creases.
. when the engine hood is opened with the
engine running.
. when the engine is turned on with the
engine hood open.
. when the driver’s seat belt is not fas-
tened.
. when the driver’s door is open.
. when the steering wheel is operated.
. when the angle of steering wheel is not
straight.
. when the Idling Stop System indicator
blinks at a low speed.
. when the fan speed control is in any
position other than “OFF” (0) while the
air flow control is in the front defroster
position. .
when the front defroster switch is on.
. when the rear window defroster switch
is on.
. When the temperature inside the vehicle
is lower than approximately 68°F
(20°C).
. When the temperature inside the vehicle
is higher than approximately 86°F
(30°C). (When the air conditioner is
off, the Idling Stop System will operate.)
. When the fan speed of the air condi-
tioner is set to the maximum speed.
. when the Idling Stop OFF switch is
turned on.
. when the power consumption is large.
. when the vehicle is traveling at altitudes
higher than 8,203 ft (2,500 m).
. when the accelerator pedal is depressed.
. when the shift lever is in the R (Reverse)
position.
. when the brake pedal is not firmly
depressed.
. when stopping the vehicle on steep
sloping roads.
NOTE:
The engine will not restart even if the brake
pedal is released while the Idling Stop
System is activated when the shift lever is
in the P (Park) position.
IDLING STOP SYSTEM (if so equipped)