Get Technical Information -> Emissions Control Guide for Honda CR-V SUV Third Generation (2006-2010)

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Emissions Controls

The burning of gasoline in your

vehicle’s engine produces several by-

products. Some of these are carbon

monoxide (CO), oxides of nitrogen

(NOx), and hydrocarbons (HC).

Gasoline evaporating from the tank

also produces hydrocarbons. Con-

trolling the production of NOx, CO,

and HC is important to the environ-

ment. Under certain conditions of

sunlight and climate, NOx and HC

react to form photochemical ‘‘smog.’’

Carbon monoxide does not contri-

bute to smog creation, but it is a

poisonous gas.

The Clean Air Act

intake manifold. They are then

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.

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.

^＊In Canada, Honda vehicles comply

with the Canadian emission

requirements, as specified in an

agreement with Environment

Canada, at the time they are

manufactured.

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.

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

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Emissions Controls

Exhaust Emissions Controls

The exhaust emissions controls

include three systems: PGM-FI,

ignition timing control, and three

way catalytic converter. These three

systems work together to control the

engine’s combustion and minimize

the amount of HC, CO, and NOx that

comes out the tailpipe. The exhaust

emissions control systems are

separate from the crankcase and

evaporative emissions control

systems.

PGM-FI System

The PGM-FI system uses sequential

multiport fuel injection.

Three Way Catalytic Converter

The three way catalytic converter is

in the exhaust system. Through

chemical reactions, it converts HC,

CO, and NOx in the engine’s exhaust

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.

2

to carbon dioxide (CO ), nitrogen

2

(N ), and water vapor.

Replacement Parts

The emissions control systems are

designed and certified to work to-

gether in reducing emissions to

levels that comply with the Clean Air

Act. To make sure the emissions

remain low, you should use only new

Honda replacement parts or their

equivalent for repairs. Using lower

quality parts may increase the

emissions from your vehicle.

Ignition Timing Control System

This system constantly adjusts the

ignition timing, reducing the amount

of HC, CO, and NOx produced.

The emissions control systems are

covered by warranties separate from

the rest of your vehicle. Read your

warranty manual for more informa-

tion.

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Three Way Catalytic Converter

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 Honda part

or its equivalent.

Keep the engine well maintained.

THREE WAY CATALYTIC CONVERTERS

Have your vehicle diagnosed and

repaired if it is misfiring, back-

firing, stalling, or otherwise not

running properly.

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 per-

formance. 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.

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Emissions Testing

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

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.

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).

1. Make sure the gas tank is nearly,

but not completely, full (around

3/4).

6. Without touching the accelerator

pedal, let the engine idle for 20

seconds.

conditions.

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).

CONTINUED

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Emissions Testing

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

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.

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).

If the testing facility determines the

readiness codes are still not set, see

your dealer.

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Technical Information -> Emissions Control for Your Honda CR-V SUV Third Generation (2006-2010)

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