ISSUE DATE:
SERVICE BULLETIN SUBJECT:
VINs or MODELS AFFECTED:
COMPLETE BY:
SERVICE BULLETIN #:

1-21-2020
800 Volt Defroster Software Update Retrofit
Service Specified Buses
Next Service Opportunity
SC-20-22

NOTICE! It is expected that this process will require 1/2 hour per bus. Please
schedule appropriately to minimize vehicle downtime.

800 VOLT DEFROSTER SOFTWARE UPDATE RETROFIT
Retrofit Description:

This procedure updates the defroster software to prevent the possibility of the defroster getting stuck
in cooling mode and to prevent the defroster from overheating.

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

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Tools/Parts Required
Tools and Supplies Required:
•
•
•
•
•

T-30 Torx Driver
Ratchet
10mm Socket
Proterra Service Laptop
Defroster Programming Cable

Parts Required:
•

None

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

2|Page

Procedure
1. Navigate to the Service Bulleting folder by clicking the following link.
\\bus.local\files\Engineering\Service Bulletins\ Copy the folder named Service Bulletin Files for
SC-20-22 to your desktop.

2. Complete the Proterra approved Lockout/Tagout procedure to make the bus safe for work.
Note: Bus power must be off for this procedure. The defroster controller will be powered by the
USB connection to the programming computer.

3. Using a T-30 Torx Driver, remove any covers to access the defroster.
4. Using a 10mm Ratchet, remove the two nuts that secure the Circuit Board Cover to the
defroster.
Note: The defroster is shown removed from the bus.

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

3|Page

5. Remove the Cover to access the Circuit Board inside it.

6. Carefully connect the Programming Cable to the Circuit Board.
Note: Make sure that the cable stays connected to the Circuit Board. The controller
may be damaged if the cable is disconnected during the programming process. A
Cable Tie may be used to hold it in place if necessary.

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

4|Page

7. Connect the other end of the Programming Cable to a free USB Port on the
Programming Computer.

8. Double Click on the folder that you saved to the desktop earlier to open it.

9. Locate the file named “Hex File Loader” in the file listing.

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

5|Page

10. Double click this file to start the programming software.

11. Click the check box shown outlined in red below.

12. Click the “Update COM ports” button outlined in red below.

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

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13. Click on the highlighted COM Port to select it.
Note: You may have a different COM Port number.

14. Click on the drop-down box on the left shown outlined in red and select the “Arduino
UNO” option. The box will be populated with the “Arduino Uno” selection.

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

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15. Click on the “Select File” button shown outlined in red below.

16. The following dialog box will appear. Click on the “020950249_3.12.2020.ino.standard”
file to select it. Click the “Open” button.

17. The following screen will appear with the selected file outlined in red. Click on the
“Upload” button to begin the programming process.

Click “Upload”

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

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18. The following screen will appear and show the progress of the update.

19. When the process is complete the following information will be displayed.

20. Press any key and the following screen will be displayed. Click the “OK” button to
complete the process.

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

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21. Disconnect the programming cable from the circuit board.
22. Using a 10mm Ratchet/Socket, replace the circuit board and the cover on the
defroster.

Paint White Dot

23. Using White Paint, paint a dot on the circuit board cover to indicate that the defroster
software has been updated. This dot should be visible from inside the dash.
24. Using a T-30 Torx Driver, replace any covers that were removed to access the
defroster.
25. Remove the Lockout/Tagout devices and return the bus to service.

Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

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