Hexagon 488LPI User manual

Propane Autogas
Engine Electrical and Sensors
Service Manual
DSM.0053 Ver. 1.0
May 26, 2022
PRINTED AND DOWNLOADED COPIES ARE UNCONTROLLED

Hexagon Agility Inc. Copyright ©2022. All Rights Reserved.
DSM.0053 Ver. 1.0 05/26/2022
488LPI Propane Autogas Engine
Electrical and Sensors Manual
Page 2 of 31

Preface
This manual is designed as a support document for trained technicians in the maintenance and service
procedures of the 488LPI™ propane autogas engine and fuel system provided by Hexagon Agility®.
No attempt shall be made to install, maintain, or repair this product until this manual and all referenced supporting
documentation have been read and fully understood.
Original Equipment Manufacturer (OEM) parts not serviced by Hexagon Agility®may be obtained by contacting
Freightliner Custom Chassis Corporation or Thomas Built Buses.
Fuel system warranty or non-warranty product support may be obtained by calling or emailing Hexagon Agility®
Customer Care and Technical Services (CCTS).
Please provide your name, phone number, email address, and complete vehicle information: VIN, year,
make, model, mileage, unit number, vehicle owner, and current vehicle location. A service advisor will
contact you to arrange vehicle repair or ship a part.
All parts must adhere to the accepted standards and ratings as specified by Hexagon Agility®. Use of
any part that is not approved by Hexagon Agility®is not recommended and may compromise the integrity
and safety of the system.
Do not remove components from original packaging until necessary. Any components that are to be
reinstalled must be thoroughly cleaned, inspected, and stored in a satisfactory manner until
reinstallation.
DSM.0053 Ver. 1.0 05/26/2022
488LPI Propane Autogas Engine
Electrical and Sensors Manual
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Table of Contents
Preface
Acronyms
Safety
Warning and Signal Words Used in this Manual
Qualified Personnel
Engine Harness Component Diagram
Repair Procedures
Camshaft Position (CMP) Sensor
Crankshaft Position (CKP) Sensor
Engine Control Module (ECM)
Engine Coolant Temperature (ECT) Sensor
Engine Harness
EVAP Purge Solenoid
Fuel By-Pass Solenoid
Fuel Pressure/Temperature (FPT) Sensor
Ignition Coil
Manifold Absolute Pressure (MAP) Sensor
Mass Air Flow (MAF) Sensor
Spark Plug Inspection
Spark Plug Wire Inspection
Torque Security Module (TSM)
References
Electrical Component and Sensor Torque Specifications
Ignition System Specifications
DSM.0053 Ver. 1.0 05/26/2022
488LPI Propane Autogas Engine
Electrical and Sensors Manual
Page 4 of 31

Acronyms
CKP
crankshaft position sensor
CMP camshaft position sensor
ECM electronic control module
ETC electronic throttle control sensor
ECT
engine coolant temperature sensor
EVAP
evaporative emissions
FPT
fuel pressure/temperature sensor
LPG
liquid propane gas
LPI Liquid Propane Injection
MAP manifold absolute pressure sensor
MAF
mass air flow sensor
TSM
torque security module
DSM.0053 Ver. 1.0 05/26/2022
488LPI Propane Autogas Engine
Electrical and Sensors Manual
Page 5 of 31

Safety
Hexagon Agility® provides safety guidelines to ensure the safety of personnel servicing and / or operating liquid
propane gas1(LPG) equipment. All personnel involved must adhere to industry standards, specialized training,
and all federal, state, and municipal laws and regulations.
Hexagon Agility®minimizes potential hazards through state-of-the art design and testing practices. Always
observe the procedures and recommendations of this manual.
Due to the presence of high-pressure and flammable fuel, LPG fuel systems are a form of hazardous energy
storage.
Warning and Signal Words Used in this Manual
WARNING indicates a hazardous situation which, if not avoided, could result in death
or serious injury.
CAUTION indicates a hazardous situation which, if not avoided, could result in minor or
moderate injury.
NOTICE is used to address practices not related to physical injury, such as best
practices or tips to help an operation or procedure go smoothly and prevent equipment
damage.
Product feature directly affects:
Safety of vehicle users, people nearby and maintenance personnel, or
Regulatory compliance.
Qualified Personnel
LPG systems must be maintained and inspected exclusively by trained personnel with qualifications in
accordance with the applicable codes.
Individuals involved in any aspect of LPG fuel system maintenance, emergency response, servicing or
testing must be properly trained. Individuals who are not trained are not permitted to service, maintain,
test, or inspect a system.
1LPG used for automotive applications is often referred to as “propane autogas.”
Critical
Characteristic
DSM.0053 Ver. 1.0 05/26/2022
488LPI Propane Autogas Engine
Electrical and Sensors Manual
Page 6 of 31

Engine Harness Component Diagram
C10
Oil
Pressure
Sensor
FRONT
C12
Camshaft
Position
Sensor
C17a
Ignition
Coil 1
C17b
Ignition
Coil 3
C17c
Ignition
Coil 5
C19a
Ignition
Coil 2
C17d
Ignition
Coil 7
C19b
Ignition
Coil 4
C19c
Ignition
Coil 6
C19d
Ignition
Coil 8
C14
Engine Coolant
Temperature
Sensor
C22
Fuel
Temperature/
Pressure
Sensor
C26
A/C
Compressor
Clutch 1
C27
A/C
Compressor
Clutch 2
C11
Crankshaft
Position
Sensor
C28
Bulkhead
Connector
C16
F
uel Injector
Harness
C6
Mass Air Flow
Sensor
C21
Ground
Ring
C20
Ground
Ring
C31
Fuel
Supply
Solenoid
C32
Fuel
By-Pass
Solenoid
C7
Manifold
Absolute
Pressure
Sensor
C9
Electronic
Throttle Control
Sensor
C15B
LH Pre-
Cat.
HEGO
Sensor
C15A
RH Pre-
Cat.
HEGO
Sensor
C4
Torque
Security
Module
C5-A
CAN 1
Terminal
Resistor
C5-B
CAN 2
Terminal
Resistor
ECM J1-C
(Gray)
ECM J1-B
(Brown)
ECM J1-A
(Black)
DSM.0053 Ver. 1.0 05/26/2022
488LPI Propane Autogas Engine
Electrical and Sensors Manual
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Repair Procedures
FRONT
DSM.0053 Ver. 1.0 05/26/2022
488LPI Propane Autogas Engine
Electrical and Sensors Manual
Page 8 of 31

Camshaft Position (CMP) Sensor Replacement
DESCRIPTION AND OPERATION
The Camshaft Position (CMP) Sensor uses electromagnetic field variations to detect Camshaft
Sprocket rotation and speed to report Camshaft position to the ECM (Electronic Control Module).
The CMP Sensor bolts to the Front Engine Cover and connects to the Engine Wiring Harness.
REMOVAL PROCEDURE
1. Secure vehicle on an approved lift and
lift vehicle.
2. Verify engine is off.
3. Disconnect CMP Sensor Electrical
Connector (2) from Engine Harness (3).
Figure 1
4. Remove CMP Sensor Retaining Bolt
(not shown)from Engine Front Cover
(1). Figure 1
5. Remove CMP Sensor from Engine
Front Cover (1). Figure 1
6. Inspect CMP Sensor and O-ring for
wear, cracks or other damage.
CMP Sensor must be replaced if O-
ring is damaged.
INSTALLATION PROCEDURE
1. Lubricate CMP Sensor O-ring with
clean engine oil.
2. Install CMP Sensor in Front Engine
Cover (1). Figure 1
3. Install and tighten CMP Sensor
Retaining Bolt (not shown). Refer to
Electrical Component & Sensor Torque
Specifications.
4. Connect CMP Sensor Electrical
Connector (2) to Engine Harness (3).
Figure 1
5. Lower vehicle.
6. Verify proper operation.
2
Figure 1:
Camshaft (CMP) Sensor Electrical Connector
location (2), Engine Harness (3), Engine Front
Cover (1)
1
3
DSM.0053 Ver. 1.0 05/26/2022
488LPI Propane Autogas Engine
Electrical and Sensors Manual
Page 9 of 31

Crankshaft Position (CKP) Sensor Replacement
DESCRIPTION AND OPERATION
The Crankshaft Position (CKP) Sensor detects crankshaft rotation and speed by monitoring the
Crankshaft Reluctor Wheel to report crankshaft position to the ECM (Electronic Control Module).
The CKP Sensor bolts into the passenger side of the Engine Front Cover and connects to the
Engine Wiring Harness.
REMOVAL PROCEDURE
1. Secure vehicle on approved lift and
raise vehicle.
2. Verify engine is off.
3. Disconnect CKP Sensor Electrical
Connector (2) from Engine Harness (3).
Figure 1
4. Remove CKP Sensor Retaining Bolt
(not shown)from Engine Front Cover
(1). Figure 1
5. Remove CKP Sensor from Engine
Front Cover (1). Figure 1
6. Inspect CKP Sensor and O-ring (not
shown) for wear, cracks or other
damage.
CKP Sensor must be replaced if O-
ring is damaged.
2
Figure 1:
Camshaft (CKP) Sensor Electrical Connector
location (2), Engine Front Cover (1),
Engine Harness (3)
1
3
FRONT
DSM.0053 Ver. 1.0 05/26/2022
488LPI Propane Autogas Engine
Electrical and Sensors Manual
Page 10 of 31