check engine Ram 4500 Chassis Cab 2020 Owner's Manual

4

ONBOARD DIAGNOSTIC SYSTEM — OBD II ....... 118
Onboard Diagnostic System (OBD II)
Cybersecurity..............................................118
EMISSIONS INSPECTION AND MAINTENANCE
PROGRAMS ...................................................... 119
SAFETY
SAFETY FEATURES ............................................ 120
Anti-Lock Brake System (ABS) ................. 120
Electronic Brake Control (EBC) System ...121
AUXILIARY DRIVING SYSTEMS ........................ 129
Forward Collision Warning (FCW) With
Mitigation — If Equipped............................129 Tire Pressure Monitoring System
(TPMS) .....................................................132
OCCUPANT RESTRAINT SYSTEMS .................. 141
Occupant Restraint Systems Features ....141
Important Safety Precautions ...................141Seat Belt Systems ..................................... 142Supplemental Restraint Systems (SRS) ...151Child Restraints ........................................160
Transporting Pets ....................................179
SAFETY TIPS .................................................... 180
Transporting Passengers ..........................180
Exhaust Gas ........................................... 180
Safety Checks You Should Make Inside
The Vehicle ................................................180 Periodic Safety Checks You Should Make
Outside The Vehicle ...................................182
STARTING AND OPERATING
STARTING THE ENGINE — GAS ENGINE .........183
Automatic Transmission............................ 183
Tip Start Feature ....................................... 183Keyless Enter-N-Go — Ignition ................... 184
Normal Starting Using ENGINE START/
STOP Button ............................................ 184 Cold Weather Operation
(Below –22°F Or −30°C) ......................... 187 After Starting .............................................. 187
STARTING THE ENGINE — DIESEL ENGINE .... 187
Automatic Transmission............................ 187
Keyless Enter-N-Go — Ignition ................... 188
Extreme Cold Weather .............................. 190
Normal Starting Procedure — Engine Manifold
Air Temperature Above 66°F (19°C) ....... 191 Starting Procedure — Engine Manifold Air
Temperature 0°F To 66°F
(–18°C to 19°C) ....................................... 191 Starting Procedure — Engine Manifold Air
Temperature Below 0°F (-18°C) .............. 192 Starting Fluids ............................................ 193 NORMAL OPERATION — DIESEL ENGINE ....... 194
Cold Weather Precautions ........................ 194
Engine Idling ............................................. 197
Noise .......................................................... 198
Stopping The Engine ................................. 198Idle Shutdown ............................................ 199
Programmable Maximum Vehicle Speed ..... 199

Operating Precautions .............................. 200
Cooling System Tips .................................. 200
Diesel Particulate Filter (DPF) Manual
Regeneration - If Equipped ....................... 201
ENGINE BLOCK HEATER — IF EQUIPPED ........ 201
ENGINE BREAK-IN RECOMMENDATIONS —
GAS ENGINE ...................................................... 202
ENGINE BREAK-IN RECOMMENDATIONS —
DIESEL ENGINE .................................................. 202
DIESEL EXHAUST BRAKE
(ENGINE BRAKING) ........................................... 203
PARKING BRAKE .............................................. 204
AUTOMATIC TRANSMISSION ........................... 205 Ignition Park Interlock ............................... 206Brake/Transmission Shift Interlock
System ....................................................... 206 Six–Speed Automatic Transmission —
If Equipped ................................................ 207 Eight-Speed Automatic Transmission —
If Equipped ................................................. 213
AUXILIARY SWITCHES — IF EQUIPPED ........... 218

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7
SERVICING AND MAINTENANCE
SCHEDULED SERVICING — GAS ENGINE ....... 329Maintenance Plan......................................330
Heavy Duty Use Of The Vehicle ................. 333
SCHEDULED SERVICING — DIESEL ENGINE .. 334
Oil Change Indicator System —
Cummins Diesel .........................................335 Perform Service Indicator —
Cummins Diesel ........................................335 Maintenance Plan — Cummins
Diesel Engine ............................................336
ENGINE COMPARTMENT ................................ 343
6.4L Engine ...............................................3436.7L Engine ................................................344
Checking Oil Level — Gas Engine .............345
Checking Oil Level — Diesel Engine ..........345
Adding Washer Fluid ................................345Maintenance-Free Battery .......................346
Pressure Washing ......................................346
DEALER SERVICE .............................................. 347
Engine Oil .................................................. 347Engine Oil Filter ........................................349
Engine Air Cleaner Filter .........................349
Air Conditioner Maintenance ................. 351
Accessory Drive Belt Inspection................354Draining Fuel/Water Separator Filter .....354
Engine Mounted Fuel Filter
Replacement ..............................................356 Underbody Mounted Fuel Filter
Replacement ..............................................357 Priming If The Engine Has Run
Out Of Fuel ................................................ 358 Intervention Regeneration Strategy —
Message Process Flow ............................. 359 Diesel Exhaust Fluid .................................. 359Body Lubrication ...................................... 360
Windshield Wiper Blades ........................ 360
Exhaust System ........................................ 362
Cooling System ......................................... 363
Charge Air Cooler — Inter-Cooler .............. 366
Brake System ............................................ 367Automatic Transmission............................ 368
Rear Axle And 4x4 Front Driving Axle Fluid
Level ....................................................... 370 Transfer Case ............................................ 371Noise Control System Required
Maintenance & Warranty ......................... 371
HOISTING ............................................................374
TIRES....................................................................374
Tire Safety Information ........................... 374
Tires — General Information .................... 382
Tire Types ................................................... 386
Spare Tires — If Equipped ....................... 387
Wheel And Wheel Trim Care .................. 389Tire Chains and Traction Devices ............ 390
Tire Rotation Recommendations .............. 391 DEPARTMENT OF TRANSPORTATION UNIFORM
TIRE QUALITY GRADES .................................... 392
Treadwear .................................................. 392
Traction Grades ......................................... 392Temperature Grades ................................. 393
STORING THE VEHICLE .................................. 393
BODYWORK ........................................................ 393 Protection From Atmospheric Agents ..... 393
Body And Underbody Maintenance .......... 394Preserving The Bodywork.......................... 394
INTERIORS ......................................................... 395
Seats And Fabric Parts .............................. 395
Plastic And Coated Parts........................... 396
Leather Parts ............................................. 396
Glass Surfaces .......................................... 396
TECHNICAL SPECIFICATIONS
IDENTIFICATION DATA ...................................... 397Vehicle Identification Number ................. 397
BRAKE SYSTEM ................................................ 397
Hydraulic Brake Assist — If Equipped....... 397
WHEEL AND TIRE TORQUE
SPECIFICATIONS .............................................. 397
Torque Specifications .............................. 398

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22GETTING TO KNOW YOUR VEHICLE
Additional features, such as windshield
wipers, will also not be available while the
vehicle is in the Remote Start mode.
The engine can be started two consecutive
times (two 15 minute cycles) with the key
fob. However, the ignition switch must be
placed in the ON/RUN position before you
can repeat the start sequence for a third
cycle.
To Exit Remote Start Mode Without Driving
The Vehicle
Push and release the Remote Start button one
time or allow the engine to run for the entire
15 minute cycle.
NOTE:
To avoid unintentional shut downs, the system
will disable for two seconds after receiving a
valid Remote Start request.
To Exit Remote Start Mode And Drive The
Vehicle
To exit Remote Start Mode and drive the vehicle
before the end of the 15 minute cycle, push and
release the unlock button on the key fob to
unlock the door and disarm the vehicle security alarm System (if equipped). Then, prior to the
end of the 15 minute cycle, place the ignition in
the ON/RUN position.
NOTE:
The ignition switch must be in the ON/RUN posi
-
tion in order to drive the vehicle.
Remote Start Comfort Systems — If
Equipped
When remote start is activated, the heated
steering wheel, and driver heated seat features
will automatically turn on in cold weather. In
warm weather, the driver vented seat feature
will automatically turn on when the remote start
is activated. These features will stay on through
the duration of remote start or until the ignition
switch is placed in the ON/RUN position.
NOTE:
The Remote Start Comfort System can be acti -
vated and deactivated through the Uconnect
System. Refer to “Uconnect Settings” in “Multi -
media” for further information on Remote Start
Comfort System operation.
SENTRY KEY
The Sentry Key Immobilizer system prevents
unauthorized vehicle operation by disabling the
engine. The system does not need to be armed
or activated. Operation is automatic, regardless
of whether the vehicle is locked or unlocked.
The system uses a key fob, keyless push button
ignition and a Radio Frequency (RF) receiver to
prevent unauthorized vehicle operation. There -
fore, only key fobs that are programmed to the
vehicle can be used to start and operate the
vehicle. The system cannot reprogram a key fob
obtained from another vehicle.
After placing the ignition switch in the ON/RUN
position, the vehicle security light will turn on for
three seconds for a bulb check. If the light
remains on after the bulb check, it indicates
that there is a problem with the electronics. In
addition, if the light begins to flash after the
bulb check, it indicates that someone
attempted to start the engine with an invalid key
fob. In the event that a valid key fob is used to
start the engine but there is an issue with the
vehicle electronics, the engine will start and
shut off after two seconds.

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108GETTING TO KNOW YOUR INSTRUMENT PANEL
The battery was discharged by an electrical
load left on when the vehicle was parked.
The battery was used for an extended period
with the engine not running to supply radio,
lights, chargers, +12 Volt portable appli-
ances like vacuum cleaners, game consoles
and similar devices.
What to do when an electrical load reduction
action message is present (“Battery Saver On”
or “Battery Saver Mode”)
During a trip:
Reduce power to unnecessary loads if
possible:
Turn off redundant lights (interior or exte -
rior).
Check what may be plugged in to power outlets +12 Volts, 115 Volt AC, USB ports.
Check HVAC settings (blower, tempera -
ture).
Check the audio settings (volume). After a trip:
Check if any aftermarket equipment was
installed (additional lights, upfitter electrical
accessories, audio systems, alarms) and
review specifications if any (load and Ignition
Off Draw currents).
Evaluate the latest driving cycles (distance,
driving time and parking time).
The vehicle should have service performed if
the message is still present during consecu
-
tive trips and the evaluation of the vehicle
and driving pattern did not help to identify the
cause.
WARNING LIGHTS AND MESSAGES
The warning/indicator lights will illuminate in
the instrument panel together with a dedicated
message and/or acoustic signal when appli -
cable. These indications are indicative and
precautionary and as such must not be consid -
ered as exhaustive. Always refer to the informa-
tion in this chapter in the event of a failure
indication. All active telltales will display first if
applicable. The system check menu may
appear different based upon equipment
options and current vehicle status. Some tell -
tales are optional and may not appear.
Red Warning Lights
Seat Belt Reminder Warning Light
This warning light indicates when the
driver or passenger seat belt is
unbuckled. When the ignition is first
placed in the ON/RUN or ACC/ON/
RUN position and if the driver’s seat belt is
unbuckled, a chime will sound and the light will
turn on. When driving, if the driver or front
passenger seat belt remains unbuckled, the
Seat Belt Reminder Light will flash or remain on
continuously and a chime will sound.
Refer to “Occupant Restraint Systems” in
“Safety” for further information.
Air Bag Warning Light
This warning light will illuminate to
indicate a fault with the air bag, and
will turn on for four to eight seconds
as a bulb check when the ignition is
placed in the ON/RUN or ACC/ON/RUN posi -
tion. This light will illuminate with a single chime
when a fault with the air bag has been detected,
it will stay on until the fault is cleared. If the light
is either not on during startup, stays on, or turns
on while driving, have the system inspected at
an authorized dealer as soon as possible.

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110GETTING TO KNOW YOUR INSTRUMENT PANEL
Vehicle Security Warning Light — If Equipped
This light will flash at a fast rate for
approximately 15 seconds when the
vehicle security alarm is arming, and
then will flash slowly until the vehicle
is disarmed.
Engine Coolant Temperature Warning Light
This warning light warns of an over -
heated engine condition. If the engine
coolant temperature is too high, this
indicator will illuminate and a single
chime will sound. If the temperature reaches
the upper limit, a continuous chime will sound
for four minutes or until the engine is able to
cool, whichever comes first.
If the light turns on while driving, safely pull over
and stop the vehicle. If the A/C system is on,
turn it off. Also, shift the transmission into
NEUTRAL and idle the vehicle. If the tempera -
ture reading does not return to normal, turn the
engine off immediately and call for service.
Refer to “If Your Engine Overheats” in “In Case
Of Emergency” for further information.
Battery Charge Warning Light
This warning light will illuminate when
the battery is not charging properly. If
it stays on while the engine is running,
there may be a malfunction with the
charging system. Contact an authorized dealer
as soon as possible.
This indicates a possible problem with the elec -
trical system or a related component.
Oil Pressure Warning Light
This warning light will illuminate to
indicate low engine oil pressure. If the
light turns on while driving, stop the
vehicle, shut off the engine as soon as
possible, and contact an authorized dealer. A
chime will sound when this light turns on.
Do not operate the vehicle until the cause is
corrected. This light does not indicate how
much oil is in the engine. The engine oil level
must be checked under the hood.
Oil Temperature Warning Light
This warning light will illuminate to
indicate the engine oil temperature is
high. If the light turns on while driving,
stop the vehicle and shut off the
engine as soon as possible. Wait for oil
temperature to return to normal levels.
Electronic Throttle Control (ETC) Warning
Light
This warning light will illuminate to
indicate a problem with the Electronic
Throttle Control (ETC) system. If a
problem is detected while the vehicle
is running, the light will either stay on or flash
depending on the nature of the problem. Cycle
the ignition when the vehicle is safely and
completely stopped and the transmission is
placed in the PARK position. The light should
turn off. If the light remains on with the vehicle
running, your vehicle will usually be drivable;
however, see an authorized dealer for service
as soon as possible.
NOTE:
This light may turn on if the accelerator and
brake pedals are pressed at the same time.

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GETTING TO KNOW YOUR INSTRUMENT PANEL111
If the light continues to flash when the vehicle is
running, immediate service is required and you
may experience reduced performance, an
elevated/rough idle, or engine stall and your
vehicle may require towing. The light will come
on when the ignition is placed in the ON/RUN or
ACC/ON/RUN position and remain on briefly as
a bulb check. If the light does not come on
during starting, have the system checked by an
authorized dealer.
Electric Power Steering Fault Warning Light
This warning light will turn on when
there's a fault with the Electric Power
Steering (EPS) system. Refer to
“Power Steering” in “Starting And
Operating” for further information.
Trailer Brake Disconnected Warning Light
This warning light will illuminate when
the Trailer Brake has been discon -
nected.
Refer to “Trailer Towing” in “Starting And Oper -
ating” for further information.
Transmission Temperature Warning Light — If
Equipped
This warning light will illuminate to
warn of a high transmission fluid
temperature. This may occur with
strenuous usage such as trailer
towing. If this light turns on, stop the vehicle and
run the engine at idle or slightly faster, with the
transmission in PARK or NEUTRAL, until the
light turns off. Once the light turns off, you may
continue to drive normally.
Door Open Warning Light
This indicator will illuminate when a
door is ajar/open and not fully closed.
NOTE:
If the vehicle is moving there will also be a single
chime.
Yellow Warning Lights
Adaptive Cruise Control (ACC) Fault Warning
Light — If Equipped
This warning light will illuminate to
indicate a fault in the ACC system.
Contact a local authorized dealer for
service.
For further information, refer to “Adaptive
Cruise Control (ACC)” in “Starting And Oper -
ating.”
WARNING!
Continued operation with reduced assist
could pose a safety risk to yourself and
others. Service should be obtained as soon
as possible.WARNING!
If you continue operating the vehicle when
the Transmission Temperature Warning Light
is illuminated you could cause the fluid to boil
over, come in contact with hot engine or
exhaust components and cause a fire.
CAUTION!
Continuous driving with the Transmission
Temperature Warning Light illuminated will
eventually cause severe transmission
damage or transmission failure.
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112GETTING TO KNOW YOUR INSTRUMENT PANEL
Engine Check/Malfunction Indicator Warning
Light (MIL)
The Engine Check/Malfunction Indi-
cator Light (MIL) is a part of an
Onboard Diagnostic System called
OBD II that monitors engine and auto -
matic transmission control systems. This
warning light will illuminate when the ignition is
in the ON/RUN position before engine start. If
the bulb does not come on when turning the
ignition switch from OFF to ON/RUN, have the
condition checked promptly.
Certain conditions, such as a loose or missing
gas cap, poor quality fuel, etc., may illuminate
the light after engine start. The vehicle should
be serviced if the light stays on through several
typical driving styles. In most situations, the
vehicle will drive normally and will not require
towing.
When the engine is running, the MIL may flash
to alert serious conditions that could lead to
immediate loss of power or severe catalytic
converter damage. The vehicle should be
serviced by an authorized dealer as soon as
possible if this occurs.
Electronic Stability Control (ESC) Active
Warning Light — If Equipped
This warning light will indicate when
the Electronic Stability Control system
is Active. The “ESC Indicator Light” in
the instrument cluster will come on
when the ignition is placed in the ON/RUN or
ACC/ON/RUN position, and when ESC is acti -vated. It should go out with the engine running.
If the “ESC Indicator Light” comes on continu
-
ously with the engine running, a malfunction
has been detected in the ESC system. If this
warning light remains on after several ignition
cycles, and the vehicle has been driven several
miles (kilometers) at speeds greater than
30 mph (48 km/h), see an authorized dealer as
soon as possible to have the problem diag -
nosed and corrected.
The “ESC OFF Indicator Light” and the “ESC
Indicator Light” come on momentarily each
time the ignition is placed in the ON/RUN or
ACC/ON/RUN position.
The ESC system will make buzzing or clicking
sounds when it is active. This is normal; the
sounds will stop when ESC becomes inactive.
This light will come on when the vehicle is in
an ESC event.
Electronic Stability Control (ESC) OFF
Warning Light — If Equipped
This warning light indicates the Elec -
tronic Stability Control (ESC) is off.
Each time the ignition is turned to ON/
RUN or ACC/ON/RUN, the ESC system
will be on, even if it was turned off previously.
WARNING!
A malfunctioning catalytic converter, as
referenced above, can reach higher
temperatures than in normal operating
conditions. This can cause a fire if you drive
slowly or park over flammable substances
such as dry plants, wood, cardboard, etc. This
could result in death or serious injury to the
driver, occupants or others.
CAUTION!
Prolonged driving with the Malfunction
Indicator Light (MIL) on could cause damage
to the vehicle control system. It also could
affect fuel economy and driveability. If the
MIL is flashing, severe catalytic converter
damage and power loss will soon occur.
Immediate service is required.

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GETTING TO KNOW YOUR INSTRUMENT PANEL113
Low Washer Fluid Warning Light — If
Equipped
This warning light will illuminate when
the windshield washer fluid is low.
Refer to “Engine Compartment” in “Servicing
And Maintenance” for further information.
Low Fuel Warning Light
When the fuel level reaches approxi -
mately 3.2 gal (12 L) this light will turn
on, and remain on until fuel is added.
A single warning chime will sound with Low Fuel
Warning.
Low Coolant Level Warning Light
This telltale will turn on to indicate the
vehicle coolant level is low.
Refer to “Dealer Service” in “Servicing And
Maintenance” for further information.
Loose Fuel Filler Cap Warning Light — If
Equipped
This warning light will illuminate when
the fuel filler cap is loose. Properly
close the filler cap to disengage the light. If the light does not turn off, please see an
authorized dealer.
Tire Pressure Monitoring System (TPMS)
Warning Light — If Equipped
The warning light switches on and a
message is displayed to indicate that
the tire pressure is lower than the
recommended value and/or that slow
pressure loss is occurring. In these cases,
optimal tire duration and fuel consumption may
not be guaranteed.
Should one or more tires be in the condition
mentioned above, the display will show the indi -
cations corresponding to each tire.
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recommended by the vehicle manufacturer on the vehicle
placard or tire inflation pressure label. If your
vehicle has tires of a different size than the size
indicated on the vehicle placard or tire inflation
pressure label, you should determine the
proper tire inflation pressure for those tires.
As an added safety feature, your vehicle has
been equipped with a Tire Pressure Monitoring
System (TPMS) that illuminates a low tire pres
-
sure telltale when one or more of your tires is
significantly under-inflated. Accordingly, when
the low tire pressure telltale illuminates, you
should stop and check your tires as soon as
possible, and inflate them to the proper pres -
sure. Driving on a significantly under-inflated
tire causes the tire to overheat and can lead to
tire failure. Under-inflation also reduces fuel
efficiency and tire tread life, and may affect the
vehicle’s handling and stopping ability.
Please note that the TPMS is not a substitute for
proper tire maintenance, and it is the driver’s
responsibility to maintain correct tire pressure,
even if under-inflation has not reached the level
to trigger illumination of the TPMS low tire pres -
sure telltale.
CAUTION!
Do not continue driving with one or more flat
tires as handling may be compromised. Stop
the vehicle, avoiding sharp braking and
steering. If a tire puncture occurs, repair
immediately using the dedicated tire repair
kit and contact an authorized dealer as soon
as possible.
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GETTING TO KNOW YOUR INSTRUMENT PANEL117
ECO Mode Indicator Light — If Equipped
This light will turn on when ECO Mode
is active.
Park/Headlight On Indicator Light
This indicator light will illuminate
when the park lights or headlights are
turned on.
Refer to “Exterior Lights” in “Getting To Know
Your Vehicle” for further information.
Front Fog Indicator Light — If Equipped
This indicator light will illuminate
when the front fog lights are on.
Refer to “Exterior Lights” in “Getting
To Know Your Vehicle” for further
information.
Turn Signal Indicator Lights
When the left or right turn signal is
activated, the turn signal indicator will
flash independently and the corre -
sponding exterior turn signal lamps
will flash. Turn signals can be activated when
the multifunction lever is moved down (left) or
up (right). NOTE:
A continuous chime will sound if the vehicle is
driven more than 1 mile (1.6 km) with either
turn signal on.
Check for an inoperative outside light bulb if
either indicator flashes at a rapid rate.
If equipped with fog lamps, the fog lamp
on the side of the activated turn signal
will also illuminate to provide additional
light when turning.
Cruise Control Set Indicator Light — If
Equipped
This indicator light will illuminate
when the cruise control is set to the
desired speed. Refer to “Speed
Control” in “Starting And Operating”
for further information.
Automatic Diesel Exhaust Brake Indicator
Light — If Equipped
This indicator light will illuminate
when the Diesel Exhaust Brake has
been activated, and has switched to
Automatic mode. Refer to “Diesel Exhaust Brake (Engine
Braking)” in “Starting And Operating” for further
information.
White Indicator Lights
Adaptive Cruise Control (ACC) Ready Light —
If Equipped
This light will illuminate when the
vehicle equipped with Adaptive Cruise
Control (ACC) has been turned on but
not set.
Refer to “Adaptive Cruise Control (ACC) — If
Equipped” in “Starting And Operating” for
further information.
Cruise Control Ready Indicator
This indicator light will illuminate
when the cruise control is ready, but
not set. Refer to “Speed Control” in
“Starting And Operating” for further
information.
Set Speed Display
The Set Speed Display indicator light
indicates the set speed for the Speed
Control and Adaptive Cruise Control
(ACC) settings.
3

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GETTING TO KNOW YOUR INSTRUMENT PANEL119
EMISSIONS INSPECTION AND
MAINTENANCE PROGRAMS
In some localities, it may be a legal requirement
to pass an inspection of your vehicle's emis-
sions control system. Failure to pass could
prevent vehicle registration.
For states that require an Inspection
and Maintenance (I/M), this check
verifies the “Malfunction Indicator
Light (MIL)” is functioning and is not
on when the engine is running, and that the
OBD II system is ready for testing.
Normally, the OBD II system will be ready. The
OBD II system may not be ready if your vehicle
was recently serviced, recently had a depleted
battery or a battery replacement. If the OBD II
system should be determined not ready for the
I/M test, your vehicle may fail the test.
Your vehicle has a simple ignition actuated test,
which you can use prior to going to the test
station. To check if your vehicle's OBD II system
is ready, you must do the following:
1. Cycle the ignition switch to the ON position,
but do not crank or start the engine.

NOTE:
If you crank or start the engine, you will have to
start this test over.
2. As soon as you cycle the ignition switch to the ON position, you will see the “Malfunc -
tion Indicator Light (MIL)” symbol come on
as part of a normal bulb check.
3. Approximately 15 seconds later, one of two things will happen:
The MIL will flash for about 10 seconds
and then return to being fully illuminated
until you turn OFF the ignition or start the
engine. This means that your vehicle's
OBD II system is not ready and you
should not proceed to the I/M station.
The MIL will not flash at all and will
remain fully illuminated until you place
the ignition in the off position or start the
engine. This means that your vehicle's
OBD II system is ready and you can
proceed to the I/M station. If your OBD II system is not ready,
you should
see an authorized dealer or repair facility. If your
vehicle was recently serviced or had a battery
failure or replacement, you may need to do
nothing more than drive your vehicle as you
normally would in order for your OBD II system
to update. A recheck with the above test routine
may then indicate that the system is now ready.
Regardless of whether your vehicle's OBD II
system is ready or not, if the MIL is illuminated
during normal vehicle operation you should
have your vehicle serviced before going to the I/
M station. The I/M station can fail your vehicle
because the MIL is on with the engine running.
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