2020 VOLVO XC90 TWIN ENGINE lights

STARTING AND DRIVING
445
Hill Descent Control
The function for assisting when driving down- hill (HDC 12
) is a low-speed function with
increased engine braking. The function makes it possible to increase or decrease thevehicle's speed on steep downhill gradientsby only using the accelerator pedal, withoutapplying the brakes. The function is included in the
Off Road drive
mode.
HDC is designed for driving on rough roads at low speeds and downhill gradients with slip-pery or otherwise difficult road surfaces. Thedriver does not need to use the brake pedalbut can instead focus on steering.
WARNING
HDC is only intended to be a supplemen- tary braking aid and it does not function inall situations. The driver is always ultimately responsible for operating the vehicle in a safe manner.
FunctionHill Descent Control allows the vehicle to move forward or backward at very low speedsassisted by the brake system. The driver canincrease the speed by pressing the acceleratorpedal. When the accelerator pedal is released, the vehicle will return to very low speedregardless of how steep the hill is and withoutthe brakes needing to be applied. The brakelights will illuminate when the function is acti-vated. The driver can brake to stop or slow the vehi- cle at any time by depressing the brake pedal. HDC is activated along with Low Speed Con- trol (LSC
13
), which facilitates and improves
traction and control on rough and slippery sur- faces. The system is intended to be used atlow speeds, up to approximately 40 km/h (25mph).
To keep in mind when using HDC
If the function is switched off while drivingon a steep downhill gradient, brakingeffect will be gradually reduced.
HDC can be used in gear positions
D and
R , and in manual gears 1 or 2.
It is not possible to manually shift to thirdgear or higher when HDC is active.
NOTE
When LSC with HDC is activated in theOff Road drive mode, the feel of the accel-
erator pedal and engine response will change.
NOTE
This drive mode is not designed to be used for normal street driving.
NOTE
The function is deactivated when driving at high speeds and must be reactivated atlower speeds if so desired.
Related information
Activating and deactivating Hill Descent Control using the function button (p. 446)
Changing drive mode (p. 438)
Low Speed Control (p. 443)
All Wheel Drive (AWD) (p. 431)
12
Hill Descent Control
13 Low Speed Control

STARTING AND DRIVING
* Option/accessory.
450
Preparing for a long trip
It is important to have the vehicle's systems and equipment checked carefully before driv-ing long distances.
Check that
the engine is running properly and that fuel consumption is normal
there are no leaks (fuel, oil or other fluid)
the brake pedal is functioning properly
all lights are working
‒ adjust the head-
light height if the vehicle is carrying aheavy load
tire tread depth and air pressure are atcorrect levels. Change to snow tires whendriving in areas where there is a risk ofsnowy or icy roads
the start battery is sufficiently charged
the wiper blades are in good condition
Related information
Checking tire pressure (p. 553)
Filling washer fluid (p. 656)
Winter driving (p. 450)
Economical driving (p. 446)
Vehicle modem settings (p. 527)
Loading recommendations (p. 585)
Driving with a trailer (p. 465)
Pilot Assist
* (p. 300)
Tire sealing system (p. 568)
Winter driving
It is important to check the vehicle before driving in cold/snowy conditions to makesure it can be driven safely.
Before the cold season arrives: Make sure the engine coolant contains 50% antifreeze. This mixture helps pro-tect the engine from frost erosion down toapprox. –35 °C (–31 °F). Do not mix dif-ferent types of antifreeze as this couldpose a health risk.
Keep the fuel tank well filled to preventcondensation from forming.
Check the viscosity of the engine oil. Oilwith low viscosity (thinner oil) improvescold-weather starting and reduces fuelconsumption when driving with a coldengine.
CAUTION
Low-viscosity oil should not be used with hard driving or in hot weather.
Check the condition and charge level of the start battery. Cold weather placesgreater demands on the start battery andreduces its capacity.
Use washer fluid containing antifreeze tohelp prevent ice from forming in thewasher fluid reservoir.

STARTING AND DRIVING
458
Overheating of engine and transmission
In certain driving conditions, such as driving in mountainous areas or hot weather, there isa risk of the engine or transmission overheat-ing, especially when carrying heavy loads.
Engine power may be temporarily limited.
Remove any auxiliary lights mounted in front of the grille when driving in hotweather.
If the temperature in the engine's coolingsystem becomes too high, a warning sym-bol will appear in the instrument panel along with the message
Engine
temperature High temperature Stop
safely. Pull over to a safe location and let
the engine idle for a few minutes to cool down.
If the message
Engine temperature
High temperature Turn off engine orEngine coolant Level low, turn off
engine is displayed, stop the vehicle and
turn off the engine.
If the transmission begins to overheat, an alternative gear shifting program will beselected. An integrated protective functionwill also be activated, the warning symbolwill illuminate and the message
Transmission warm Reduce speed to
lower temperature or Transmission hot
Stop safely, wait for cooling will be dis- played in the instrument panel. Follow the recommendations given by reducingspeed or stopping the vehicle safely andletting the engine idle for a few minutes tolet the transmission cool.
If the vehicle begins to overheat, the airconditioning may be temporarily switchedoff.
After a prolonged period of driving indemanding conditions, do not turn off theengine immediately after stopping.
NOTE
It is normal for the engine's cooling fan to operate for a short time after the engine isswitched off.
Symbols in the instrument panel
Symbol Meaning
High engine temperature. Follow the recommendations provided.
Low coolant level. Follow the recommendations provided.
Transmission hot/overheated/ cooling. Follow the recommen-dations provided.
Related information
Refilling coolant (p. 610)
Driving with a trailer (p. 465)
Preparing for a long trip (p. 450)

STARTING AND DRIVING
}}
459
Battery drain
The electrical functions in the vehicle drain the battery to varying degrees. Avoid usingignition mode II when the engine is switched
off. Use ignition mode I instead, as this uses
less electrical current.
Note that certain accessories may also drain power from the electrical system. Do not usefunctions that use a lot of electrical currentwhen the engine is turned off. Examples ofsuch functions are: blower
headlights
windshield wipers
audio system (especially at high volume).
If the starter battery voltage is low, a message is shown in the driver display. The vehicle'senergy-saving function will then turn off orreduce certain functions, such as the blowerand/or the audio system.
–Charge the battery by starting the engine and let it run for at least 15 minutes (driv-ing charges the battery faster than lettingthe engine idle).
Related information
Start battery (p. 613)
Ignition modes (p. 415)
Jump starting using another battery If the start battery is discharged, current from another battery can be used to start the vehi-cle.
Jumper cable connecting points.
CAUTION
The charging point of the vehicle is only intended for jump starting the vehicle inquestion. The charging point is notintended for jump-starting another vehicle.Using the charging point to start anothervehicle could cause a fuse to blow, whichwould cause the charging point to stopworking.
If a fuse has blown, 12 V Battery Fuse failure
Service required will be displayed in the instrument panel. Volvo recommends contact- ing an authorized Volvo workshop. To avoid short circuits or other damage, the following steps are recommended when jumpstarting the battery:

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STARTING AND DRIVING
4601. Put the ignition in mode
0.
2. Make sure the auxiliary battery (the bat- tery used to jump start the discharged battery) has a voltage of 12 volts.
3. If the auxiliary battery is in another vehicle, turn off that vehicle's engine and makesure that the vehicles are not touchingeach other.
4. Clamp the red jumper cable onto the auxil- iary battery's positive (+) terminal (1).
CAUTION
Connect the jump cable carefully to pre- vent short circuits with other componentsin the engine compartment.
5. Fold back the cover over your vehicle's positive (+) jump start terminal (2).
6. Clamp the other end of the red jumper cable to your vehicle's positive (+) jump start terminal (2).
7. Clamp the black jumper cable onto the auxiliary battery's negative (-) terminal (3).
8. Clamp the other end of the black jumper cable to your vehicle's negative (-) groundpoint (4). 9. Make sure the jumper cables are securely
attached to help prevent sparks whilejump starting.
10. Start the engine of the assisting vehicle and let it run for a few minutes at a higheridling speed than normal, about1500 rpm.
11. Start your vehicle's engine. If the engine does not start, allow an additional 10minutes of charging time and then try tostart the engine again.
NOTE
When the engine is started under normal conditions, the vehicle's electrical drivemotor is prioritized – the gasoline engineremains off. This means that after the startknob has been turned clockwise, the elec-tric motor has "started" and the vehicle isready to be driven. Start of the electricmotor is indicated by the indicator lights onthe instrument panel going out and its pre-selected theme illuminating.
CAUTION
Do not touch the connections between the cable and the vehicle during the startattempt. Risk of sparking.
12. Remove the jumper cables in the reverseorder ‒ first the black cables and then the
red cables. Make sure that none of the clamps of the black jumper cables come into contactwith either vehicle's positive (+) jump startterminals or either of the red jumpercable's connected clamps.
WARNING
PROPOSITION 65 WARNING! Battery
posts, terminals, and related accessories contain lead and lead compounds, chemi-cals known to the state of California tocause cancer and reproductive harm. Washhands after handling.
WARNING
Batteries generate hydrogen gas, which is flammable and explosive.
Do not connect the jumper cable toany part of the fuel system or to anymoving parts. Avoid touching hotmanifolds.
Battery fluid contains sulfuric acid. Donot allow battery fluid to contact eyes,skin, fabrics or painted surfaces.
If contact occurs, flush the affectedarea immediately with water. Obtain

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STARTING AND DRIVING
* Option/accessory.
466
NOTE
Extreme weather conditions, towing a trailer, high altitude and lower fuel gradethan recommended are factors that cansignificantly increase the vehicle's fuel con-sumption.
Trailer weights
WARNING
Please adhere to the recommendations provided for trailer weight. If the recom-mendations are not followed, the vehicleand trailer may be difficult to control duringevasive maneuvers and braking.
NOTE
The specified maximum trailer weights are those permitted by Volvo. National vehicleregulations may set additional restrictionson trailer weight and speed. The trailerhitches may be certified for higher towingweights than the vehicle is permitted totow.
Self-leveling suspension *The vehicle's self-leveling system attempts to keep the vehicle at a constant level, regardlessof load (up to the maximum permitted weight).When the vehicle is stationary, the rear end of the vehicle will be slightly lowered, which isnormal.
Driving in hilly terrain or hot weatherIn certain conditions, there is a risk of over-heating when driving with a trailer. If overheat-ing of the engine and drive system is detected,a warning symbol will illuminate in the instru-ment panel and a message will appear. The automatic transmission selects the opti- mal gear for the current load and enginespeed.
Steep inclines
Do not lock the automatic transmission into a higher gear than what the engine can handle
‒
it is not always preferable to drive in highgears at low rpm.
Parking on a hill
1. Depress the brake pedal.
2. Apply the parking brake.
3. Put the gear selector in P.
4. Release the brake pedal.Put chocks behind the wheels when the vehi- cle is parked on a hill with a trailer attached.
Starting on a hill
1. Depress the brake pedal.
2. Put the gear selector in D.
3. Release the parking brake.
4. Release the brake pedal and start driving.
Related information
Trailer Stability Assist
* (p. 467)
Checking trailer lights (p. 468)
Towing capacity and tongue weight (p. 667)
Overheating of engine and transmission(p. 458)
Retractable hitch
* (p. 461)

STARTING AND DRIVING
* Option/accessory.
468
Checking trailer lights
When connecting a trailer, make sure that all of the lights on the trailer are functioningbefore starting to drive.
Trailer turn signals and brake lightsIf one or more of the turn signals or brake lights on the trailer is not working, a symboland message will be displayed in the instru-ment panel. The other lights on the trailermust be checked manually by the driver beforethe vehicle is driven.
Symbol Message
Trailer turn indicator Right
turn indicator malfunction
Trailer turn indicator Left
turn indicator malfunction
Trailer brake light Malfunc-
tion
If any of the trailer's turn signal lights is not working, the turn signal symbol in the instru-ment panel will also flash more quickly thannormal.
Trailer rear fog lightWhen a trailer is connected, the vehicle's rearfog light may not illuminate and rear fog lightfunctionality is instead transferred to the trailer. If this is the case, check to see if thetrailer is equipped with a rear fog light beforeactivating the vehicle's fog lights when drivingwith a trailer to help ensure safe operation.
Checking trailer lights
*
Automatic check
When the trailer has been connected to the vehicle's electrical system, its lights can bechecked by automatically activating them.This function helps the driver check that thetrailer's lights are functioning correctly beforestarting to drive. In order to perform this check, the vehicle must be switched off.
1. When a trailer is connected to the towbar,
the message
Automatic Trailer Lamp
Check will appear in the instrument panel.
2. Acknowledge the message by pressing the O button on the right-side steering
wheel keypad.
> The light check will begin.
3. Get out of the vehicle to perform the check.
> All of the lights on the trailer will beginflashing, and then illuminate separately one at a time.
4. Visually check that all of the trailer's lights are functioning correctly. 5. After a short time, all of the trailer's lights
will start flashing again.
> The light check is completed.
Disabling the automatic check
The automatic light check can be disabled in the center display. 1.Tap
Settings in the Top view.
2. Tap
My CarLights and Lighting.
3. Deselect
Automatic Trailer Lamp
Check.
Manual check
If the automatic check has been disabled, the check can be started manually. 1. Tap
Settings in the Top view.
2. Tap
My CarLights and Lighting.
3. Select
Manual Trailer Lamp Check.
> The light check will begin. Get out of the vehicle to perform the check.
Related information
Driving with a trailer (p. 465)

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MAINTENANCE AND SERVICE
598
How can I prepare for my next OBD II
emission inspection?
If your Check Engine (MIL) light is lit or was lit but went out without service, haveyour vehicle diagnosed and, if necessary,serviced by a qualified Volvo technician.
If you recently had service for a lit CheckEngine light, or if you had service thatrequired disconnecting the battery, aperiod of driving is necessary to bring theOBD II system to "ready" for inspection.Two half-hour trips of mixed stop-and-go/highway driving are typically needed toallow OBD II to reach readiness. YourVolvo retailer can provide you with moreinformation on planning a trip.
Maintain your vehicle in accordance withyour vehicle's maintenance schedule.
Owner maintenancePeriodic maintenance requirements and inter-vals are described in your vehicle's Warrantyand Service Records Information booklet. The following points can be carried out between the normally scheduled maintenance services.
Each time the vehicle is refueled:
Check the engine oil level.
Clean the windshield, windshield wipers, headlights, and taillights.
Monthly:
Check cold tire pressure in all tires. Inspect the tires for wear.
Check that engine coolant and other fluidlevels are between the indicated "min"and "max" markings.
Clean interior glass surfaces with a glasscleaner and soft paper towels.
Wipe driver information displays with asoft cloth.
Visually inspect battery terminals for cor-rosion. Corrosion may indicate a loose ter-minal connector, or a battery near the endof its useful service life. Consult your Volvoretailer for additional information.
As needed:
Wash the vehicle, including the undercarriage, to reduce wear that can be caused by abuildup of dirt, and corrosion that can becaused by salt residues. Clean leaves and twigs from air intake vents at the base of the windshield, and from other pla-ces where they may collect.
NOTE
Complete service information for qualified technicians is available online for purchaseor subscription at www.volvotechinfo.com.
Related information
Vehicle status (p. 601)
Scheduling service and repairs (p. 601)
Connecting equipment to the vehicle's data link connector (p. 39)
Technician certification (p. 40)
Climate control system service (p. 605)
Maintenance of the brake system (p. 420)
Engine compartment overview (p. 607)