August 2016

This notice applies to your vehicle, VIN: .
Dear :
As the owner of a model year compressed
natural gas (CNG) equipped vehicle, your satisfaction with our product is very important to us.
General Motors has become aware of a small number of vehicles with leaks in the manual
shut-off valve. If this condition affects your vehicle you may noticed the CNG odor or hear a
hissing sound.
To check for this condition, please have a certified CNG technician inspect the manual shut-off
valve in accordance with GM Service Information procedures for CNG leakage and damage.
This inspection should be performed regularly as part of the updated maintenance schedule. If
the inspection is performed at a GM dealership, and your vehicle is still covered under its 5
year/50,000 mile (80,000 km) Emissions Control Systems Warranty, replacement of the
manual shut-off valve, if required, will be performed for you at no charge.
Additionally, we are updating the maintenance schedule in the CNG supplement to your owner
manual to include regular inspection of the CNG manual shut-off valve. The enclosed insert is
an amendment to your supplement. Please keep this insert with your important vehicle
documents for reference.
If you have any questions or concerns that your dealer is unable to resolve, please contact the
appropriate Customer Assistance Center at .
We sincerely regret any inconvenience or concern that this situation may cause you. We want
you to know that we will do our best, throughout your ownership experience, to ensure that
your provides you with many miles of enjoyable driving.

Enclosure
17650

GLOBAL SAFETY FIELD INVESTIGATIONS
DCS4153
URGENT - DISTRIBUTE IMMEDIATELY
Date:

August 22, 2016

Subject: Customer Advisory Letter Mailing - GM Reference #17650
CNG Shutoff Valve Updated Maintenance Schedule
Models: 2011-2016 Chevrolet Express
2013-2016 Chevrolet Silverado HD
2015-2016 Chevrolet Impala
2011-2016 GMC Savana
2013-2016 GMC Sierra HD
Equipped with Vehicle Fuel - Bi-Fuel & Monovalent plus CNG (RPO
FHV), Vehicle Fuel - Dedicated CNG (RPO FHZ), Engine - LPG/CNG,
6.0L V8 (RPO LC8), Engine - Gas, 3.6L (RPO LFR), Parts Pkg. Complete Vehicle Kit, 3 Tank (RPO UFM), or Parts Pkg. - Complete
Vehicle Kit, 4 Tank (RPO UFP)
To:

All Chevrolet and GMC Dealers

Attention: General Manager, Service Advisor, Service Manager, Parts and
Service Director, Parts Manager, and New and Used Vehicle Sales
Manager
General Motors has become aware of a small number of vehicles with leaks in
the manual shut-off valve. The attached customer advisory letter and owner
manual inserts advise how and when to have the valve inspected. Additionally,
we are updating the maintenance schedule in the CNG supplement of the
owner manual to include regular inspection of the CNG manual shut-off valve.
Sales Managers are to print the owner manual insert locally and insert a
copy into the CNG supplement owner manual of involved vehicles, for both
used and new vehicle inventory, prior to delivering the vehicle to the owner.
Due to the small number of vehicles involved and due to limited initial parts
availability, dealers are encouraged not to order parts for use as shelf stock.
Parts should only be ordered when inspection determines that it is necessary to
replace a manual shut-off valve.
General Motors will begin mailing letters to involved customers on August 30,
2016 to inform them of an updated CNG Maintenance Schedule. These letters
will be mailed in phases; phase 1 will include Express and Savana, phase 2 will
include Silverado HD and Sierra HD, and phase 3 will include Impala.
A list of involved vehicles is attached to this message. A copy of the letter and
the Owner Manual inserts by model are attached to this message.

END OF MESSAGE
GLOBAL SAFETY FIELD INVESTIGATIONS

Amendment to the 2011 - 2016 Chevrolet Express/GMC Savana CNG
Compressed Natural Gas Supplement
This information replaces the
Maintenance Schedule subsection
in the Service and Maintenence
section of the Compressed Natural
Gas Supplement to your Owner
Manual.

Maintenance Schedule
This CNG vehicle requires special
maintenance that is in addition to
the routine maintenance provided in
the owner manual, such as fluids,
filters, etc. The CNG system
components require periodic visual
inspections and maintenance by a
CSA International-certified inspector
or authorized GM dealer—see your
dealer or http://www.csagroup.org/.
CNG fuel filler neck lines and cargo
tank high-pressure flex lines require
inspection at least every 12 months
or 12 000 km/7,500 mi, whichever
comes first. CNG fuel tank(s), tank
shields and valves require
inspection at least every 36 months
or 58 000 km/36,000 mi, whichever

comes first. These and other
required inspections are designated
in the Maintenance Schedule chart
in this section.
Have required services performed
by your GM dealer or other qualified
repair facility. Your dealer has the
necessary training and parts to
repair the vehicle.

{ Warning
The tank shields are designed to
protect the CNG tank in a crash
and from road hazards. Removal
of the shields may result in tank
damage that could result in a
rupture or possible explosion of
the tank. You or others could be
injured or even killed. If you must
remove a tank shield for any
reason, e.g., tank inspection or
vehicle repair, always reinstall the
shield before operating the
vehicle.

{ Warning
The CNG fuel system and tank(s)
must be inspected by a certified
inspector if the vehicle is involved
in a motor vehicle accident or fire
or if the system is leaking,
corroded or otherwise damaged
in any way. Have the tank
inspected if it emits an odor or
hissing sound.
The CNG fuel tank(s) must be
replaced 15 years after
manufacture. The expiration date of
the fuel tank(s) and instructions for
inspections are on a label on the
fuel tank(s) and on the fuel door.
Have an authorized GM dealer
replace the fuel tank(s). Do not
reuse old fuel tank(s).

2

{ Warning
Keeping a CNG fuel tank in
service after the tank service
expiration date is dangerous. The
tank may no longer withstand the
CNG fuel system operating
pressure. You could be severely
injured or killed. Take the vehicle
to an authorized GM dealer to
have the tank replaced.

1 2 0 0 0 k m /7 ,5 0 0 m i

2 4 0 0 0 k m /1 5 ,0 0 0 m i

3 6 0 0 0 k m /2 2 ,5 0 0 m i

4 8 0 0 0 k m /3 0 ,0 0 0 m i

6 0 0 0 0 k m /3 7 ,5 0 0 m i

7 2 0 0 0 k m /4 5 ,0 0 0 m i

8 4 0 0 0 k m /5 2 ,5 0 0 m i

9 6 0 0 0 k m /6 0 ,0 0 0 m i

1 0 8 0 0 0 k m /6 7 ,5 0 0 m i

1 2 0 0 0 0 k m /7 5 ,0 0 0 m i

1 3 2 0 0 0 k m /8 2 ,5 0 0 m i

1 4 4 0 0 0 k m /9 0 ,0 0 0 m i

1 5 6 0 0 0 k m /9 7 ,5 0 0 m i

1 6 8 0 0 0 k m /1 0 5 ,0 0 0 m i

1 8 0 0 0 0 k m /11 2 ,5 0 0 m i

1 9 2 0 0 0 k m /1 2 0 ,0 0 0 m i

2 0 4 0 0 0 k m /1 2 7 ,5 0 0 m i

2 1 6 0 0 0 k m /1 3 5 ,0 0 0 m i

2 2 8 0 0 0 k m /1 4 2 ,5 0 0 m i

2 4 0 0 0 0 k m /1 5 0 ,0 0 0 m i

3

Visually inspect each CNG connection for
leaks. (2)

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Visually inspect CNG fill receptacle for a
damaged or missing O-ring. (2)

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Visually inspect all CNG hoses and lines for leaks
or damage. (2)

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Inspect the manual shutoff valve and connections
for damage or leaks. (2)

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Maintenance Schedule
Additional Required
Services (1)

Drain high pressure filter. (3)
Replace high pressure filter element. (4)
Visually inspect CNG tank shields for damage or
contact to fuel tank(s). (5)
Visually inspect fuel tank valves for leaks or
damage. (5)
Visual inspection of CNG tank(s) by certified
inspector for damage and deterioration. (5)

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4
Footnotes — Maintenance
Schedule Additional Required
Services
(1) Continue with the specified
maintenance intervals for the life of
the vehicle.
(2) Or every 12 months, whichever
comes first.
(3) Or every 24 months, whichever
comes first.
(4) Or every 96 months, whichever
comes first.
(5) Every 36 months or 58 000 km/
36,000 mi, whichever comes first.
See instructions on fuel container
for inspection and service life.

Amendment to the 2013 - 2016 Chevrolet Silverado/GMC Sierra Bi-Fuel
(Gasoline/CNG) Supplement
This information replaces the
Maintenance Schedule subsection
in the Service and Maintenance
section of the Gasoline/Compressed
Natural Gas Supplement to your
Owner Manual.

Maintenance Schedule
This CNG vehicle requires special
maintenance that is in addition to
the routine maintenance provided in
the owner manual, such as fluids,
filters, etc. The CNG system
components require periodic visual
inspections and maintenance by a
CSA International-certified inspector
or authorized GM dealer—see your
dealer or http://www.csagroup.org/.

{ Warning

{ Warning

The tank shield protects the fuel
tank in a crash and from road
hazards. Operation with the shield
removed may result in tank
damage that could result in a
rupture or possible explosion of
the tank. You or others could be
injured or even killed. If you must
remove a tank shield for any
reason, e.g., tank inspection or
vehicle repair, always reinstall the
shield before operating the
vehicle.

Keeping a CNG fuel tank in
service after the tank service
expiration date is dangerous. The
tank may no longer withstand the
CNG fuel system operating
pressure. You could be severely
injured or killed. Take the vehicle
to an authorized GM dealer to
have the tank replaced.

Have required services performed
by your GM dealer or other qualified
repair facility. Your dealer has the
necessary training and parts to
repair the vehicle.

©

2016 General Motors LLC. All Rights Reserved.

2

{ Warning
The CNG fuel system and tank(s)
must be inspected by a certified
inspector if the vehicle is involved
in a motor vehicle accident or fire
or if the system is leaking,
corroded or otherwise damaged
in any way. Have the tank
inspected if it emits an odor or
hissing sound.

The CNG fuel tank(s) must be
replaced 15 years after
manufacture. The expiration date of
the fuel tank(s) and instructions for
inspections are on a label on the
fuel tank(s) and on the fuel door.
Have an authorized GM dealer
replace the fuel tank(s). Do not
reuse old fuel tank(s).

1 2 0 0 0 k m /7 ,5 0 0 m i

2 4 0 0 0 k m /1 5 ,0 0 0 m i

3 6 0 0 0 k m /2 2 ,5 0 0 m i

4 8 0 0 0 k m /3 0 ,0 0 0 m i

6 0 0 0 0 k m /3 7 ,5 0 0 m i

7 2 0 0 0 k m /4 5 ,0 0 0 m i

8 4 0 0 0 k m /5 2 ,5 0 0 m i

9 6 0 0 0 k m /6 0 ,0 0 0 m i

1 0 8 0 0 0 k m /6 7 ,5 0 0 m i

1 2 0 0 0 0 k m /7 5 ,0 0 0 m i

1 3 2 0 0 0 k m /8 2 ,5 0 0 m i

1 4 4 0 0 0 k m /9 0 ,0 0 0 m i

1 5 6 0 0 0 k m /9 7 ,5 0 0 m i

1 6 8 0 0 0 k m /1 0 5 ,0 0 0 m i

1 8 0 0 0 0 k m /11 2 ,5 0 0 m i

1 9 2 0 0 0 k m /1 2 0 ,0 0 0 m i

2 0 4 0 0 0 k m /1 2 7 ,5 0 0 m i

2 1 6 0 0 0 k m /1 3 5 ,0 0 0 m i

2 2 8 0 0 0 k m /1 4 2 ,5 0 0 m i

2 4 0 0 0 0 k m /1 5 0 ,0 0 0 m i

3

Visually inspect each CNG connection for
leaks. (2)

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