Field Service Bulletin
Defective Blue iQ™ Harness Causing
Inoperative Fuel Gauge and Transmission MIL
ENP-715
May 6, 2019
Copyright ©2019. Agility Fuel Solutions. All Rights Reserved.

1. Introduction
A defective wire harness in some Blue iQ™ fuel systems may cause the in-dash fuel gauge
to become inoperative or may cause the transmission malfunction indicator light (MIL) to
illuminate.
The Blue iQ on-board diagnostics (OBD) harness has four connectors. Two large circular
connectors are inserted between the vehicle OBD connector and OBD port, a three-pin
connector (NOTE: only two terminals are populated) connects to the CAN interface bus,
and a two-pin connector connects to the Blue iQ Smart Gauge. Figure 1
The OBD harness is located behind the vehicle dash, usually near the steering wheel and
below the ignition key switch.
Remove and replace defective OBD harness to correct the issue and return vehicle to
normal operation.

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Figure 1.
A correct Blue iQ harness, Agility part number 10400740, showing male OBD connector (1),
female OBD connector (2), CAN interface bus connector (3), Smart Gauge connector (4).
®

1.1 Warning Messages Used in this Bulletin
.⚠ CAUTION.
Damage to equipment, engine, fuel system or vehicle is possible if instructions are not
followed.
.NOTICE .
Best practices or hints to help an operation or procedure go smoothly.

2. Affected Units
Agility Fuel Solutions Blue iQ CNG fuel systems for Freightliner or Kenworth vehicles.
Approximately 183 systems produced between May and August 2018.

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3. Corrective Action
Remove and replace defective Blue iQ wire harness.

4. Tools and Materials
▪ Common hand tools (to access and open dashboard area)
▪ Replacement Blue iQ OBD Harness, Agility Fuel Solutions p/n 10400740. The new
harness is labelled with the part number and the revision number: Rev A.

5. Procedure
If vehicle fuel gauge is not working properly, or vehicle transmission MIL is illuminated and
there is no transmission problem, examine Blue iQ wire harness located behind the dash.

⚠ CAUTION.
Observe all safety measures for CNG vehicle repair including all facility requirements.

⚠ CAUTION.
▪ Park vehicle, set parking brake, remove ignition key, and secure vehicle tires with wheel
chocks.
▪ If equipped: Lock out/tag out battery disconnect.
5.1. Inspection
Blue iQ wire harnesses are made by two manufacturers and differ in visual defects.
5.1.1. Defect 1, Manufacturer 1
Multiple wires connecting to a single point create an unreliable joint. Inspect harness for
two indicators:
1. Manufacturer label that reads “10400740 Rev -”. Figure 2
2. One green and one yellow wire are not visible at the circled area. Figure 2

Figure 2.
Green and yellow wires are not visible in defective wire harness 10400740 from Manufacturer 1.

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Correct wire harness has visible green and yellow wires. Figure 3

Figure 3.
Correct OBD harness, p/n 10400740 from Manufacturer 1 has visible green and yellow wires.

5.1.2. Defect 2, Manufacturer 2
Wire connections between the OBD connector and CAN interface bus are missing. Inspect
harness for two indicators:
1. Manufacturer label that reads “KE” and “10400740 Rev -”.
2. Green and yellow CAN interface wires run directly from the OBD connector to the
CAN connector but do not connect to Smart Gauge wires. Figure 4

Manufacturer label reads
as follows:
“Part # Rev –” and “KE”

Figure 4.
Wires connecting OBD connectors to CAN interface bus are missing, and supplier label reads
“Part# Rev –” and “KE” in this defective wire harness 10400740 from Manufacturer 2.

Correct wire harness has visible green and yellow wires. Figure 5

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Figure 5.
Correct Blue iQ OBD harness, p/n 10400740, from Manufacturer 2
should have green and yellow wires (circled) visible.

5.2. Remove and Replace Wire Harness
1. Unplug Blue iQ OBD wire harness as follows (Figure 1):
a. Unplug CAN interface bus connector (3) from CAN interface bus.
b. Unplug Smart Gauge connector (4) from Smart Gauge.
c. Unplug male OBD connector (1) from vehicle OBD port and female OBD
connector (2) from OEM OBD cable connector by twisting and pulling connectors
apart.
2. Install new Blue iQ OBD harness as follows (Figure 1):
a. Plug male OBD connector (1) into vehicle OBD port and female OBD connector
(2) into OEM OBD cable connector by aligning and twisting connectors together.
b. Plug CAN interface bus connector (3) into CAN interface bus.
c. Plug Smart Gauge connector (4) into Smart Gauge.
3. If equipped: Remove lock out/tag out battery disconnect.
4. If transmission fuel gauge was inoperable, verify proper fuel gauge operation.
5. If transmission MIL was illuminated, verify proper transmission function.
6. Update vehicle maintenance and repair records.
7. Remove wheel chocks.
8. Return vehicle to service.

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6. Warranty Information
This procedure is covered under warranty. Standard repair time (SRT) is 0.3 hours. Please
refer to Warranty Manual, ENP-067, for warranty reimbursement procedures.
For parts and support, contact Agility Fuel Solutions Customer Care:
+1 949 267 7745
+1 855 500 2445 (toll-free, U.S. and Canada)
[email protected]
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 Solutions to its customers and clients is solely for the
use of those customers and clients. No portion of this publication may be reproduced or
distributed without express written consent of Agility Fuel Solutions. Agility Fuel Solutions
reserves the right to utilize the intellectual property contained within this publication as
content for any other publication produced by Agility Fuel Solutions.
Trademark Notice
Agility® and TUFFSHELL® are registered trademarks of Agility Fuel Solutions. Drop-N-Go™
is a trademark of Agility Fuel Solutions. Trademarks of other manufacturers are the
property of their respective companies.
Agility Fuel Solutions | 3335 Susan Street Suite 100 | Costa Mesa, CA 92626 USA
www.agilityfuelsolutions.com
Revision
--

Description
Initial Release

ENP-715: Defective Blue iQ™ OBD Harness

Author
C. Grasso

Approved By
Team

Date
05/06/2019

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