MACS Service Reports - 2016 - JAN8

GET FAMILIAR WITH GRILLE SHUTTERS

Paul Weissler

less, but EPA has all sorts of numerical "rounding" in its methodology. But a 1.0 mpg better window sticker number and a 1.0
gram/mile in the carbon credits that convert to mpg for CAFE
is a double benefit, therefore very cost-effective for the car maker
who has to meet the regulations. Even on passenger cars, the
grille shutters carry a credit; only 0.6 gram/mile (plus whatever
improvement in window sticker you might get). So at Chrysler,
which is selling a lot of Ram pickups with the 5.7-liter Hemi V8,
there's a need for CAFE credits (which also accounts for the early
move to R-1234yf, which carries a huge CAFE credit).
It's important to understand that the shutters are open from
idle up to about 35 mph, so there's maximum airflow through
the front end cooling module for good cooling. They close at
higher road speed when the ram airflow is sufficient. The closing of the shutters provides better front-end aerodynamics,
hence the better fuel economy on the EPA highway cycle. ■

Figure 11 Active grille shutters used on a number of FCA (Fiat Chrysler
Automobiles) products to improve fuel economy. Shown is the system on
the Ram 1500 pickup.

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Active grille shutters (Figure 11) are slowly going into more
and more late-model vehicles, but the installations are being
carefully selected. The reason is that the credits which OEMs
receive are in a menu of CAFE (Corporate Average Fuel Economy) credits with an overall cap, so the vehicle manufacturers
may also want to see a measurable improvement in highway
fuel economy before they make the investment. Active grille
shutters have the potential to improve vehicle aerodynamics,
but the improvement must be 3% in order to get the full CAFE
credit. And the improvement must be for "active" aero, which
means a device that physically makes a change. A 3% improvement is a lower number on a truck, and as a result one of the "active" things that can be done is installation of the pivoting grille
shutters.
On the Ram 1500 for example, Chrysler was able to demonstrate a 1.0 mpg improvement in the window sticker, and that's
why the Ram pickup was the first Chrysler product with the
feature. Now that 1.0 mpg boost might actually be somewhat

Figure 12: If grille shutters actuator housing is unplugged at location
shown, the engine control system will log a loss of communications (Ucode).

As we noted, the system came in first on the Ram 1500 (in 2013). Shortly afterward
(also 2013) it was installed on the 2013 Dodge Dart, then the 2014 Jeep Cherokee
and for 2015 appears on the new Chrysler 200. We say a shop should get familiar
with the grille shutters for a few reasons, the most important of which are:
* A failure that leaves the shutters stuck closed could cause overheating in lower
speed driving.
* A condition that causes the shutters to be packed with road film or snow. If the
shutters can move, there won't be a trouble code or MIL. But the vehicle may run hot
in other than deep winter cold.

* A trouble code that applies to the shutter system. Ram pickups have logged
P1D73, which is a performance failure code for the shutters and yes, it will turn on
the check engine light.
*Here's another active grille shutters code that turns on the check engine light, but
it occurs after the truck has been serviced, a procedure in which the front fascia
was removed. The code U11E9 may be live or stored, and it's triggered when the
system's harness connector was disconnected as part of other service (Figure 12). A
simple check to see if the actuator housing unlatched retainer will tell the tale.

MACS Service Reports is published monthly by the Mobile Air Conditioning Society Worldwide. It is distributed to members of MACS Worldwide
and is intended for the educational use of members of the automotive air
conditioning service and repair industry. Suggestions for articles will be
considered for publication, however, MACS Worldwide reserves the right
to choose and edit all submissions.

Editors:
Elvis Hoffpauir, Steve Schaeber
Production Designer:
Laina Casey
Manager of Service Training:
Steve Schaeber
Mobile Air Conditioning Society Worldwide
P.O. Box 88, Lansdale, PA 19446
Phone: (215) 631-7020 * Fax: (215) 631-7017
Email: membership@macsw.org * Website: www.macsw.org

Unless otherwise noted, all photos/art by author.

January 2016

MACS Service Reports

http://www.techauthority.com http://www.macsw.org

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