Field Service Bulletin
CNG System
Fuel Cap Sensor Triggers (Magnets)
ENP-209, Rev. B
September 25, 2014

1. Introduction
Magnets inside the Agility Fuel Systems aluminum fill receptacle caps may fall out and
prevent the vehicle engine from cranking.
When the cap is properly seated, the magnet closes the reed switch on the fill panel,
sending an “OK to crank” signal to the engine control unit (ECU). If the magnets are not
present, the signal is not sent to the ECU, and the engine cannot crank.

Magnets (A) in the fuel receptacle cap
and a reed switch (B) on the fill panel
are part of the Agility Fuel Systems
Drive Away Prevention feature. The
magnet must actuate the switch to
enable engine cranking.

2. Affected Units
This procedure applies to Agility Fuel Systems 24300004, 243xx000, 263xx000, 256xx000,
246xx000 CNG fill panels and auxiliary fill panels.

3. Temporary Fix to Enable Vehicle Start and Operation
1. Since there are 2 magnets (sensor triggers) per cap, and 1 reed switch (sensor) in
the system, the OK to start signal can be enabled if one magnet is still in the cap -the cap may be rotated so the remaining magnet can trigger the sensor.
2. The cap should be repaired (installing missing magnets) or replaced at the next
opportunity for driver convenience.

CNG Fuel Cap Sensor Triggers

2 of 4

4. Parts and Supplies Needed
1.
2.

3.

Reed Sensor Trigger (Magnet), Agility Fuel Systems Part Number 10400139 (old
part number 10400106), quantity as needed.
Two part epoxy adhesive, such as Dev-Con 5-Minute Epoxy (available at any
hardware store and many office supply stores nationwide.) DO NOT use 1-part
adhesives (such as “super glue” or silicone glue which can fail).
Cleaning swabs and alcohol.
NOTE

A kit for replacing the sensor trigger magnets is available. Order the Agility Fuel
Systems Fill Cap Sensor Trigger Kit, Part Number 10303042, which includes 4
magnets and a package of epoxy, enough to repair two fill caps.

5. Procedure – Magnet Replacement
1.
2.
3.

4.

5.

Remove the cap from the fill panel.
Using a swab, clean the magnet and the hole with alcohol and allow to dry.
Follow the mixing instructions for the 2-part epoxy. Insert some epoxy into the hole
and on the magnet. Push the magnet into the hole until it is flush with the rim surface
on the cap. If the magnet is too deep, it may not actuate the reed switch.
Wipe away any excess epoxy with a paper towel. Place a piece of masking tape over
the magnet and the hole to prevent the magnet from pushing out. When the epoxy
cures, remove the masking tape.
To protect the finish and hold the cap steady, place it into a wooden fixture with a
hole to accommodate the tether attachment post. A scrap piece of 2x4 may be used
for this.

After the epoxy has cured, use a
center punch to make 4 dimples
near the magnet.

CNG Fuel Cap Sensor Triggers

A repaired cap showing the magnet
in place and the 4 center-punched
dimples near the magnet.

3 of 4

6.

Using a center punch, make 4 dimples on either side of the magnet on the bottom
face of the cap. Note the punch should be held at an approximate angle of 10°. The
depth of the dimple should be between 0.040-0.050 inches. From the edge of the
magnet hole to the center of the dimple should be approximately 0.050-in.
NOTE: The magnet is a very strong rare-Earth type, and will pull the center
punch toward it, so you must hold the center punch firmly. If you miss and
punch the magnet, it will likely be destroyed, and it will be difficult to remove and
replace. An automatic center punch, set to maximum depth, is recommended for
this step. The main idea is to distort the hole to tighten the bore around the
magnet.

7.

Standard repair time (SRT) is 0.5 hours and is covered under warranty.

Contact Agility Fuel Systems Product Support at 1-949-267-7745 or [email protected]
for more information.
Agility Fuel Systems
1815 Carnegie Ave
Santa Ana, CA 92705 USA
[email protected]
www.agilityfs.com

Proprietary Statement
The information provided within this document is proprietary and confidential. All prior
versions, including updates and revisions forwarded separately, are proprietary. The
information provided by Agility Fuel Systems to its customers and clients is solely for the
use of those customers and clients. No portion of this manual may be reproduced or
distributed without express written consent of Agility Fuel Systems. Agility Fuel Systems
reserves the right to utilize the intellectual property contained within this publication as
content for any other publication produced by Agility Fuel Systems.

Revision

Description

Author

Approved By

Date

--

Initial Release

W. Yoshida

Y. Coy

7/24/14

A

Added kit info
Magnet part
number change

W. Yoshida

Y. Coy

9/8/14

W. Yoshida

J. Laycock

9/23/14

B

CNG Fuel Cap Sensor Triggers

4 of 4