2012 Acura MDX Owner's Manual

Your vehicle has also been equipped
with a TPMS malfunction indicator to
indicate when the system is not
operating properly. The TPMS
malfunction indicator is combined
with the low tire pressure telltale.
When the system detects a
malfunction, the telltale will flash for
approximately one minute and then
remain continuously illuminated.
This sequence will continue upon
subsequent vehicle start-ups as long
as the malfunction exists.
When the malfunction indicator is
illuminated, the system may not be
able to detect or signal low tire
pressure as intended.
TPMS malfunctions may occur for a
variety of reasons, including the
installation of replacement or
alternate tires or wheels on the
vehicle that prevent the TPMS from
functioning properly.Always check the TPMS malfunction
telltale after replacing one or more
tires or wheels on your vehicle to
ensure that the replacement or
alternate tires and wheels allow the
TPMS to continue to function
properly.Tire Pressure Monitoring System (TPMS)－Required Federal Explanation586

The burning of gasoline in your
vehicle's engine produces several
byproducts. Some of these are
carbon monoxide (CO), oxides of
nitrogen (NOx), and hydrocarbons
(HC). Gasoline evaporating from the
tank also produces hydrocarbons.
Controlling the production of NOx,
CO, and HC is important to the
environment. Under certain
conditions of sunlight and climate,
NOx and HC react to form
photochemical‘‘smog.’’Carbon
monoxide does not contribute to
smog creation, but it is a poisonous
gas.The Clean Air Act
The United States Clean Air Act
ᤳ
sets standards for automobile
emissions. It also requires that
automobile manufacturers explain to
owners how their emissions controls
work and what to do to maintain
them. This section summarizes how
the emissions controls work.
Scheduled maintenance is on page
514.ᤳ
In Canada, Acura vehicles comply
with the Canadian emission
requirements, as specified in an
agreement with Environment
Canada, at the time they are
manufactured.Crankcase Emissions Control
System
Your vehicle has a positive crankcase
ventilation system. This keeps
gasses that build up in the engine's
crankcase from going into the
atmosphere. The positive crankcase
ventilation valve routes them from
the crankcase back to the intake
manifold. They are then drawn into
the engine and burned.
Evaporative Emissions Control
System
As gasoline evaporates in the fuel
tank, an evaporative emissions
control canister filled with charcoal
adsorbs the vapor. It is stored in this
canister while the engine is off. After
the engine is started and warmed up,
the vapor is drawn into the engine
and burned during driving.
CONTINUED
Emissions Controls
587
Technical Information

Onboard Refueling Vapor
Recovery
The onboard refueling vapor
recovery (ORVR) system captures
the fuel vapors during refueling. The
vapors are adsorbed in a canister
filled with activated carbon. While
driving, the fuel vapors are drawn
into the engine and burned off.
Exhaust Emissions Controls
The exhaust emissions controls
include four systems: PGM-FI,
ignition timing control, exhaust gas
recirculation, and three way catalytic
converter. These four systems work
together to control the engine's
combustion and minimize the
amount of HC, CO, and NOx that
come out the tailpipe. The exhaust
emissions control systems are
separate from the crankcase and
evaporative emissions control
systems.
PGM-FI SystemThe PGM-FI system uses sequential
multiport fuel injection. It has three
subsystems: air intake, engine
control, and fuel control. The
powertrain control module (PCM)
uses various sensors to determine
how much air is going into the
engine. It then controls how much
fuel to inject under all operating
conditions.Ignition Timing Control SystemThis system constantly adjusts the
ignition timing, reducing the amount
of HC, CO, and NOx produced.Exhaust Gas Recirculation (EGR)
SystemThe exhaust gas recirculation (EGR)
system takes some of the exhaust
gas and routes it back into the intake
manifold. Adding exhaust gas to the
air/fuel mixture reduces the amount
of NOx produced when the fuel is
burned.
Three Way Catalytic ConverterThe three way catalytic converter is
in the exhaust system. Through
chemical reactions, it converts HC,
CO, and NOx in the engine's exhaust
to carbon dioxide (CO
2), nitrogen
(N
2), and water vapor.
Replacement Parts
The emissions control systems are
designed and certified to work
together in reducing emissions to
levels that comply with the Clean Air
Act. To make sure the emissions
remain low, you should use only new
Acura replacement parts or their
equivalent for repairs. Using lower
quality parts may increase the
emissions from your vehicle.
The emissions control systems are
covered by warranties separate from
the rest of your vehicle. Read your
warranty manual for more
information.
Emissions Controls588

The three way catalytic converter
contains precious metals that serve
as catalysts, promoting chemical
reactions to convert the exhaust
gasses without affecting the metals.
The catalytic converter is referred to
as a three-way catalyst, since it acts
on HC, CO, and NOx. A replacement
unit must be an original Acura part or
its equivalent.
The three way catalytic converter
must operate at a high temperature
for the chemical reactions to take
place. It can set on fire any
combustible materials that come
near it. Park your vehicle away from
high grass, dry leaves, or other
flammables.
A defective three way catalytic
converter contributes to air pollution,
and can impair your engine's
performance. Follow these
guidelines to protect your vehicle's
three way catalytic converter.●
Always use unleaded gasoline.
Even a small amount of leaded
gasoline can contaminate the
catalyst metals, making the three
way catalytic converter ineffective.
●
Keep the engine well maintained.
●
Have your vehicle diagnosed and
repaired if it is misfiring,
backfiring, stalling, or otherwise
not running properly.
THREE WAY CATALYTIC CONVERTER
WARM UP THREE WAY CATALYTIC
CONVERTERS
Three Way Catalytic Converter
589
Technical Information

Testing of Readiness Codes
If you take your vehicle for an
emissions test shortly after the
battery has been disconnected or
gone dead, it may not pass the test.
This is because of certain‘‘readiness
codes’’that must be set in the on-
board diagnostics for the emissions
systems. These codes are erased
when the battery is disconnected,
and set again only after several days
of driving under a variety of
conditions.If the testing facility determines that
the readiness codes are not set, you
will be requested to return at a later
date to complete the test. If you must
get the vehicle retested within the
next two or three days, you can
condition the vehicle for retesting by
doing the following.
1. Make sure the gas tank is nearly,
but not completely, full (around
3/4).
2. Make sure the vehicle has been
parked with the engine off for 6
hours or more.
3. Make sure the ambient
temperature is between 40° and
95°F (4° and 35°C).4. Without touching the accelerator
pedal, start the engine, and let it
idle for 20 seconds.
5. Keep the vehicle in Park. Increase
the engine speed to 2,000 rpm, and
hold it there until the temperature
gauge rises to at least 1/4 of the
scale (about 3 minutes).
6. Without touching the accelerator
pedal, let the engine idle for 20
seconds.Emissions Testing590

7. Select a nearby lightly traveled
major highway where you can
maintain a speed of 50 to 60 mph
(80 to 97 km/h) for at least 20
minutes. Drive on the highway in
D. Do not use the cruise control.
When traffic allows, drive for 90
seconds without moving the
accelerator pedal. (Vehicle speed
may vary slightly; this is okay.) If
you cannot do this for a continuous
90 seconds because of traffic
conditions, drive for at least 30
seconds, then repeat it two more
times (for a total of 90 seconds).8. Then drive in city/suburban traffic
for at least 10 minutes. When
traffic conditions allow, let the
vehicle coast for several seconds
without using the accelerator pedal
or the brake pedal.9. Make sure the vehicle has been
parked with the engine off for 30
minutes.
If the testing facility determines the
readiness codes are still not set, see
your dealer.
Emissions Testing
591
Technical Information

592

Client Service Information
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594
Warranty Coverages
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595
Reporting Safety Defects
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596
Authorized Manuals
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597
Warranty and Client Relations
593
Warranty and Client Relations