INSTRUCTION TO SERVICE
ITS: 61756

DATE 06/08/2026

SECTION:

231 – Cooling System

SUBJECT:

Hybrid System Cooling Pump Replacement

ISSUE:

Pump shuts off for a brief 9-10 seconds due to an internal firmware issue.

SUMMARY:

Instructions to remove OEM pump and replace with a pump with updated
firmware

ITS61756
Ref. NHTSA Recall No.
Not Applicable

Ref. Transport Canada Recall No.
Not Applicable

THIS ITS DOCUMENT SHOULD BE RETAINED AND REFERRED TO FOR FUTURE MAINTENANCE UNTIL
THE NEW FLYER PARTS AND/OR SERVICE MANUAL IS UPDATED TO REFLECT WORK DONE AS A
RESULT OF THIS DOCUMENT. ENSURE THAT THIS DOCUMENT IS AVAILABLE FOR PARTS AND
MAINTENANCE STAFF GOING FORWARD.
This document and the contents discussed herein are the confidential and proprietary information of New Flyer Industries Canada
ULC and New Flyer of America Inc. and are disclosed by New Flyer in confidence. This document and the contents herein are not
to be disclosed by the intended recipient without the prior written authorization of New Flyer. Any unauthorized disclosure,
reproduction or other distribution of this document or information strictly prohibited and may result in action being taken against
the party making the unauthorized disclosure. This document and all copies hereof must be returned to New Flyer upon request.

INSTRUCTION TO SERVICE
ITS61756

PROCEDURE:
1. Ensure to apply parking brake.
2. Turn the main battery disconnect switch to the “OFF” position.
3. Gain access to the electronic cooling package on the roof of the bus.As required, open the rooftop ECP
cover.
WARNING: Working on the roof of the bus requires appropriate scaffolding and/or fall protection
harnesses. When the roof side panels are open, take care to step over the panels from the scaffold to the
roof of the bus. Do not step on the open side panel, they will not support your weight and a fall could
result.
4. Place a suitable container beneath coolant pump hoses to be disconnected.
5. Disconnect coolant supply and return hoses from the coolant pump.
6. Clamp off the coolant hoses.

Figure 1: Remove Coolant Pump
7. Disconnect the low voltage connectors from the pump.
8. Remove the hardware mounting the coolant pump.

Disconnect
LV Connectors

Remove Hardware

Figure 2: Remove Coolant Pump

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INSTRUCTION TO SERVICE
ITS61756
9. Replace the existing pump with the new coolant pump.
10. Set the removed coolant pumps aside and send them back to supplier. Reach out to RPSM for shipping
instructions and details.
11. Reuse hardware, apply loctite-243 and torque to 9-10 ft-lbs.
12. Connect low voltage connectors of the pump to HRNS-INV ROOF RACK connectors, VEPI/DTI CLNT PUMPXCCCAN and VEPI/DTI CLNT PUMP-TWR.

Reconnect
LV Connectors

Reinstall Hardware

Figure 3: Install New Coolant Pump
13. Reconnect coolant supply and return coolant hoses to the new pump.
14. Torque ideal waveseal clamps (NF PN: 553153) to 80 in-lbs, dry. Tighten at 75 rpm or less, re-torque to 80 inlbs at 75 rpm or less after 30 minutes.

Torque Clamps

Figure 4: Reconnect Coolant Hoses
15. Top up the cooling system with proper coolant until full. Opening of the drain valve may be required to get
coolant flowing. Close drain valve immediately after coolant starts flowing.

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INSTRUCTION TO SERVICE
ITS61756
16. Using the pump switch, located near the inverter cooler, start the cooling system water pump running at its
lowest allowable speed while continuing to fill the coolant tank. During this process, the coolant level will drop.
Continue to add coolant trying to maintain the coolant level at cold max until constant fluid level is achieved in
the expansion tank. Caution should be taken to ensure that you do not over fill the tank beyond hot max.
17. Allow the system to sit for 10 minutes to allow any entrapped air to collect.
18. Repeat steps 15 and 16 until a constant fluid level is achieved in the expansion tank.
19. Remove all tools and debris from work area to return coach to service.
20. Please ensure the latest PLC and IP programs are loaded into the vehicle.
21. Remove the lock out tag and turn the Hight Voltage Interlock Switch to the “ON” position.
22. Turn the main battery disconnect switch to the “ON” position.

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INSTRUCTION TO SERVICE
ITS61756

LABOUR ESTIMATE
Operation
1

Remove and replace hybrid system coolant pump

Number of
Technician(s)
1

Hours
2

Labor Time
T X HR
2

PARTS REQUIRED
Item

Part Number

1

553153

Qty.
per
Coach

Description
CLAMP-IDEAL WAVESEAL 1.13 - 1.56

Units

Notes

2

EA

As Required

Qty.

Units

Notes

SPECIAL TOOLS REQUIRED
Item

ITS61756

Part Number

Description

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June 8, 2026