Group:
Bulletin No.:
Issue Date:

TECHNICAL

0 – GENERAL
SB-14-027
01-22-2014

SERVICE BULLETIN

COE HYBRID SAFETY PRACTICES
SUBJECT VEHICLES:
Hybrid COE models
HYBRID VEHICLE SERVICE PRECAUTIONS:
The following items outline the recommended safety practices when working on a Hybrid COE truck.
WARNING: The hybrid HV (high voltage) system contains a high voltage battery and high voltage circuits.
Improper handling of these components can result in serious injury of death due to electrical shock. Only
technicians with special Hybrid training should perform service on these vehicles. Ensure that all work is
performed correctly following the procedures set forth within this publication.
BEFORE YOU BEGIN:
- Read and understand all instructions and procedures before you begin the work.
- Confirm that someone other than the technician working on the truck has CPR (Cardio Pulmonary
Resuscitation) training and there is an AED (Automated External Defibrillator) on sight.
- Read and follow all NOTICES and WARNINGS set forth in this publication. These alerts help to avoid damage
to components, serious personal injury, or both.
- Park the vehicle on a level and solid surface and apply the parking brake.
- Confirm the engine is stopped, the ignition switch is in the off (LOCK) position, and the key is removed.
- Wear safety glasses to prevent eye injuries.
- Place wheel chocks in front of and behind all wheels.
1. Technicians performing maintenance or repair on the HV system must have previously received training on
the Hino COE Hybrid system.
2. Create a safety zone and surround the work area with orange cones to notify people in the area that high
voltage service is being performed. During work on the HV system, display a placard which states “Caution
High Voltage Work, Do Not Touch this Vehicle!” or words with similar language.

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Bulletin No.:
Issue Date:

TECHNICAL

0 – GENERAL
SB-14-027
01-22-2014

SERVICE BULLETIN

3. ALWAYS remove any loose hanging badges, jewelry, bracelets, belt, or wrist watches or any metal item
prior to service of the HV system.

4. Always wear Hybrid specific, high voltage insulating gloves (Class 0 1000V), safety glasses and insulated
shoes when performing maintenance or repair of the HV system.

5. NEVER use insulating gloves that have
expired. Prior to each use of the insulating
gloves, confirm that the certification date,
stamped on the gloves, is within 6 months of
the current usage date. The gloves need to
be recertified after every six months of use
by an approved facility. Check the gloves for
cracks, tears, or damage by rolling the gloves
to check for air leaks. Do not use any leaking
gloves.
CAUTION: The leather portion of the glove
must be worn over the red rubber portion of
the glove.

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TECHNICAL

0 – GENERAL
SB-14-027
01-22-2014

SERVICE BULLETIN

6. Remove the 4 bolts and the service plug cover. Retain the bolts for reinstallation.

7. Confirm the ignition switch is in the off (LOCK) position and the key is removed. The HV system
service plug must be removed any time the HV system is being serviced. Always wait a minimum of
seven (7) minutes after the service plug has been removed before beginning service on the HV
system to allow the system time to fully power down. Place the service plug in a secure location
which is out of sight to prevent someone from accidentally connecting it to the vehicle while service
is being performed. For safety, reinstall the service plug cover and retaining bolts while the service
plug is removed for service of the HV system.
CAUTION: NEVER turn the ignition switch to the “ON” position any time the service plug is removed.
This can result in damage to the vehicle’s electrical system and create fault codes.

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8. Disconnect the negative terminal of the
12 volt battery.

9. While performing service, ensure
that the work area is clear of loose
metal objects such as socket
extensions, bolts, etc. which could
cause HV circuits to short circuit if
dropped. Always use the Hybrid
Insulated Tool kit (No. HDT-195HVST)
provided when working with HV
circuits or terminals. NEVER use
other tools.

10. High voltage circuit harnesses
are colored ORANGE. NEVER touch
the connections of these high
voltage circuits unless required to
do so.

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TECHNICAL

SERVICE BULLETIN

11. Remove the 4 push pin retainers from underneath the Hybrid battery unit and retain for
reinstallation.

12. Remove the four (4) retaining
bolts and the terminal inspection
cover and retain for reinstallation.

13. ALWAYS wear the hybrid-specific
insulating gloves before touching any
high voltage circuit, and verify that
the voltage on that circuit is at 0V
(zero voltage) using a Megger Meter.
The meter is shown in the
photograph to the right. The Megger
Meter must be able to generate up to
1000V DC and deliver a resistance
value in Mega ohms.

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14. Ground the Megger Meter to
the inverter case. Verify that the
meter operates properly on a 12V
system prior to performing any
high voltage checks. This will
ensure proper operation of the
meter.
NEVER use two hands to check
voltage readings. Using only one
hand (the one hand rule), check
each terminal within the inverter
opening for any voltage on the 5
terminals. The Megger Meter
should indicate .01 volts or less on
each terminal and circuit.

15. After removal of high voltage
terminals, immediately insulate
their connectors using electrical
tape to prevent electrical shock or
short circuit.

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SERVICE BULLETIN

16. When reinstalling the U, W, and V cables into the inverter, be certain to install them into the
correct positions. Refer to the photograph, below, and the corresponding labels on each cable. Install
the 6 bolts which retain the U, W, and V cables to the inverter and tighten them to the specified
torque.
WARNING: ALWAYS use the insulated tools and insulated gloves during this step. Such use is
required. Failure to wear high voltage safety gloves may result in personal injury or death due to
electrical shock.
NOTICE: Tighten the cable side of each wire before tightening the terminal side.
Specified Torque: 7 lb-ft (9 Nm)

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SERVICE BULLETIN

17. After repairs have been completed on the HV system, an insulation test is required on the HV
cables any time service is performed to confirm that no voltage leaks are present in the electrical
insulation of the cables. Measure the insulation resistance from the U-Phase to ground, the W-Phase
to ground, and the V-Phase to ground. Make certain that the insulation resistance is 10 Mega ohms
or greater.
NOTICE: Never measure insulation resistance between each phase (U, W, V) terminal of three-phase
cable connector side. See Figure 2, below.
WARNING: ALWAYS use high voltage safety gloves during this step. Failure to wear high voltage
safety gloves may result in personal injury or death due to electrical shock.

18. Install the four (4) retaining bolts and
the terminal inspection cover. Tighten the
bolts to the specified torque.
Specified Torque: 7 lb-ft (9 Nm)

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19. Install the service cover using the 4 clips
which were previously removed.

Clips

20. Connect the negative terminal of the
12 volt battery.

21. Double check the torque of the HV circuit terminals, and verify that no loose parts or tools have
been left behind prior to installing the service plug.

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SB-14-027
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SERVICE BULLETIN

22. Remove the service plug cover. Install the service plug into the HV battery. Ensure that the
locking lever is fully engaged and is slid towards the rear of the vehicle. Install the 4 bolts into the
service plug cover. Tighten the bolts to the specified torque.
Specified Torque: 7 lb-ft (9 Nm)

WARNING: Be certain that all steps of the Hybrid Vehicle Service Precautions procedure, specified
above, have been completed prior to performing this Repair Procedure. Failure to properly perform
the HV system service disconnect, and complete all steps of the procedure, can result in personal
injury or death due to electrical shock.

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