24

Gray

25

Black / White

DAP 3,4,5 Return*

26

Black / White

Fuel Compartment Temperature Sensor 2
(Thermistor 2) Return

27

-

28

Green

J1939 CAN (+)

29

Yellow

J1939 CAN (–)

30

-

31

Pink / Black

OEM Fuel Gauge Signal
DAP Lamp (if equipped)

Fuel Compartment Temperature Sensor 2
(Thermistor 2) Signal

LP Lamp Return (if equipped)
DAP 3
DAP 3,4,5 Return*
DAP 4
DAP 3,4,5 Return*
DAP 5

LP Lamp Signal (if equipped)

*Installer choice; consult vehicle-specific wiring manual.

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2.9. SAE J1939 CAN connectors
Blue iQ interfaces with OEM vehicle data through several SAE J1939 CAN chassis harness connectors. FIGURE
2–36a and FIGURE 2–36b

J1939 CAN connection configurations vary according to vehicle OEM and model.

connector image

connector end view

*See
NOTICE
below

‘

FIGURE 2–36a. SAE J1939 circuit schematic and connector views – FSCM harness

SAE J1939 circuit connector pin out

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Pin

Color

Circuit

A

Yellow

J1939 CAN (+)

B

Green

J1939 CAN (–)

C

PLUG

–

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connector image

connector end view

*See
NOTICE
below
FIGURE 2–36b. SAE J1939 circuit schematic and connector views – bulkhead harness

SAE J1939 circuit connector pin out

Pin

Color

Circuit

A

Yellow

J1939 CAN (+)

B

Green

J1939 CAN (–)

C

PLUG

–

J1939 bus should connect to OEM vehicle 500K network unless otherwise specified.

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Blue iQ bulkhead
connector

(Optional) Y-connector
J1939 harness

to OEM harness

Y-connector
J1939 harness

FIGURE 2–37. SAE J1939 circuit connector end view and typical system locations. NOTE: Y-connector not used

on all vehicle configurations.

Please contact Hexagon Agility® CCTS for vehicle specific details.

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2.10. SAE J1939 CAN Blue iQ Gauge Harness
An additional Blue iQ harness consisting of a 9-pin bulkhead connector, a 3-pin J1939 CAN bus connector, and
a 2-pin connector links the Blue iQ gauge to the vehicle via the OEM J1939 OBD CAN port. FIGURES 2–38 and 239

Blue iQ gauge harness

Blue iQ gauge J1939 CAN
to OEM harness

FIGURE 2–38. Typical SAE J1939 circuit harness and Blue iQ gauge harness (refer to Section 2.1)

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connector image

connector image

NOTE: some systems use a non-flanged male connector.

1

J1939 OBD Port,
Male

J1939 OBD Port,
Female

2

Connector end view

Harness end
(wire) view

OEM Fuel Gauge CAN Connection
(OPTIONAL)

Blue iQ Gauge CAN Connection

OPTIONAL:
Some
systems are
equipped
with a
second Blue
IQ gauge.

Blue iQ Gauge

FIGURE 2–39. Secondary SAE J1939 circuit and connector views

Secondary SAE J1939 connector circuit pin out –
3-pin connector to fuel system

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Pin

Color

Circuit

A

Yellow

J1939 CAN (+)

B

Green

J1939 CAN (–)

C

PLUG

–

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Secondary SAE J1939 connector circuit pin out –
2-pin connector to Blue iQ gauge

Pin

Color

Circuit

1

Yellow

J1939 CAN (+)

2

Green

J1939 CAN (–)

2.11. OEM Fuel Gauge Conditioning Circuit
Blue iQ interfaces with the OEM vehicle fuel gauge via a conditioning circuit. FIGURE 2–40

FIGURE 2–40. OEM fuel gauge conditioning circuit (circle) location taped to Blue iQ FMM harness in a box FMM.

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Connectors – side view

Connector cutaway view
1

4

5

Connector end view (rear view)

BLANK

5 V Return

8

1

7

2

6

3

5

4

to Harness Splice
BLANK
PWM Signal

FIGURE 2–41. OEM fuel gauge conditioning circuit connector end views.
Some Blue iQ systems do not use connectors shown in FIGURE 2-41. Instead, terminating
resistors are soldered, sealed, and packaged inside the FMM Blue iQ harness.

OEM fuel gauge conditioning circuit diagram
White

White

White

Black/
White

FSCM Pin 21 is a pulse width modulation (PWM) signal. Therefore, resistance cannot be
measured with the system energized. The Blue iQ chassis harness must be disconnected
from both the FSCM and the bulkhead connector to properly measure resistance in the
OEM fuel gauge circuit.

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OEM fuel gauge conditioning circuit pin out

Pin

Color

Circuit

1

White

to Splice 8

2

–

–

3

–

–

4

White

PWM Signal

5

Black/White

5V Return

6

–

–

7

–

–

8

–

–

2.12. (Optional) OEM Vehicle Interface
On certain fuel system configurations, Blue iQ interfaces with key OEM vehicle functions via an 8-pin connector
and a bulkhead connector. FIGURE 2–42 Functions communicated through the OEM vehicle interface include the
following items.
1. Key (Ignition) On
5. J1939 CAN (+)
2. DAP Lamp
6. J1393 CAN (–)
3. Low Fuel
7. Battery (+)
4. Fuel Gauge Signal

FIGURE 2–42. Optional OEM vehicle interface harness (8-pin connector circled).

Please contact Hexagon Agility® CCTS for vehicle specific details.
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2.13. Blue iQ System Schematic
Please refer to Appendix A (below).

3. Fault Code Diagnostics
3.1. Fault Code (FC) Lists
FC

Title

5572

Engine Gaseous Fuel Pressure Regulator Intake
Pressure - Data Valid But Above Normal Operating
Range – Moderately Severe Level

6845

Engine Gaseous Fuel Temperature Regulator Intake
Temperature Sensor Circuit –
Voltage Below Normal or Shorted to Low Source

6849

Gaseous Fuel High Pressure Shutoff Valve –
Current Below Normal or Open Circuit

Solenoid power is open circuit (less than 0.3
A current flow)

6857

Fuel System Control Module –
Data Erratic, Intermittent, or Incorrect

Common interface fault – Information only to
engine. Indicates that data from engine is not
received at normal update rate.

6858

Fuel System Control Module –
Abnormal Update Rate

Common interface fault – Information only to
engine. Indicates that data from engine is not
received at normal update rate.

6947

Fuel Tank Receptacle Cover –
Mechanical System Not Responding or Out of
Adjustment

Receptacle cover open at time of crank
request, crank prevented

6955

Fuel Tank Receptacle Cover Detached During
Operation –
Condition Exists

Receptacle cover
operation

6958

Gaseous Fuel High Pressure Shutoff Valve Circuit –
Current Above Normal or Grounded Circuit

6963

Fuel Storage Compartment 1 Temperature - Data
Valid But Above Normal Operating Range –
Most Severe Level

7194

Fuel System Control Module - Data Valid But Below
Normal Operating Range –
Least Severe Level

Engine Inlet Pressure drops below 30 psi
(0.21 MPa) after engine crank start, crank
aborted

7195

Fuel System Control Module - Data Valid But Below
Normal Operating Range –
Moderately Severe Level

Engine Inlet Pressure below 60 psi (0.41
MPa) at time of crank request, crank
prevented

7264

Gaseous Fuel High Pressure Shutoff Valve - Data
Valid But Above Normal Operating Range –
Moderately Severe Level

Supply solenoid valve (SSV) coil resistance
greater than normal

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Description

Pressure/temperature transducer pressure
above 4500 psi (31 MPa) for more than 2.5
seconds
Pressure/temperature transducer
temperature circuit shorted to ground or
open circuit for more than 0.5 seconds

open