Rear Mounted Ultracapacitors Improperly Programmed – 2014-2021 Gillig Low Floor Transit Buses

April 25, 2022 NHTSA CAMPAIGN NUMBER: 22V276000

Rear Mounted Ultracapacitors Improperly Programmed

The engine may be started unexpectedly, increasing the risk of injury to anyone nearby the engine compartment during maintenance operations.

 

NHTSA Campaign Number: 22V276

Manufacturer Gillig, LLC

Components ELECTRICAL SYSTEM

Potential Number of Units Affected 592

 

Summary

Gillig, LLC (Gillig) is recalling certain 2014-2021 Low Floor transit buses. The rear-mounted ultracapacitors may allow the engine to be started when the master battery disconnect switch is in the “OFF” position.

 

Remedy

Dealers will update the software for the buses equipped with the Vanner Ultracapacitor system, and conduct a hard rewire for the buses equipped with the KBI system, free of charge. Owner notification letters were mailed on June 22, 2022. Owners may contact Gillig’s customer service at 1-510-264-5073 for 1-800-735-1500.

 

Notes

Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to www.nhtsa.gov.

 

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Gillig has decided that certain model year 2014 through 2021 Low Floor Diesel transit buses, manufactured between 05/21/2014 and 11/10/2021 and equipped with an optional auxiliary energy ultracapacitor feature contain a defect related to motor vehicle safety. In the affected vehicles, a flaw in the design of the controls for the rear chassis mounted ultracapacitors prevents it from detecting that the master battery disconnect switch is in the “OFF” position and may continue to energize the 24-volt battery.

Even with the master battery disconnect switch in the OFF position, if the 24-volt battery is energized and the ignition run switch is turned ON and the engine start button is depressed, the engine may start unexpectedly, posing an increased risk of injury to personnel present or performing maintenance operations in or around the engine compartment at that time.

As a result of the above, GILLIG has decided to voluntarily initiate a safety recall campaign of the vehicle population that may be affected by the issue.

 

What The Issue Is:

With the battery disconnect switch in the “OFF” position, the engine can be started via the ignition run switch and the engine can start unexpectedly and continue to run for several minutes, until the ultracapacitor power is drained.

 

What We Are Asking You To Do:

1. On your Model Year 2014 through 2021 buses equipped with the Vanner supercapacitor system p.n. 13-72000-001/002, GILLIG is asking you to reprogram the supercapacitor controller with a new software update

2. On your Model Year 2019 through 2021 buses equipped with the KBI supercapacitor system p.n. 13-72017-006, GILLIG is asking you to perform a hard wire update of the supercapacitor system

 

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Chronology of Defect / Noncompliance Determination

GILLIG produces a limited number of low floor transit buses with rear chassis mounted ultracapacitors which are used as a supplemental source of power during engine starting.  Prior to performing any maintenance operations in the engine compartment of any GILLIG buses (including buses with rear chassis mounted ultracapacitors), there are a series of standard, redundant precautions that are required to be followed to prevent the engine from being started while maintenance personnel are in the vicinity of the engine.  Initially, the ignition select switch in the rear of the bus should be placed in an OFF position.  In addition, users are instructed to attach a “Do Not Operate” tag on the engine start switches and controls.  These redundant, independent precautions are supposed to take place prior to starting any maintenance on the bus.  Finally, users are instructed before starting the vehicle to ensure all personnel are safely clear of the bus.

 

In November 2020, a GILLIG Field Service Representative at a customer location for an unrelated issue was advised by the customer that it was possible on their buses with a rear chassis mounted ultracapacitor to start the buses with the master battery disconnect switch in the OFF position.  The GILLIG representative inspected several of the customers buses with a Vanner model rear chassis mounted ultracapacitor and was eventually able to confirm that the bus engine could be started from the front of the bus, even though the bus main battery was turned off.  Gillig, Vanner and the customer worked through an iterative process over the next few months, to develop a solution for this issue.  In March 2021, Gillig loaded new software onto three of the customer’s buses to understand whether the software would ensure the ultracapacitor contactors remain deenergized and in an open state when the main bus battery is in the OFF position.  In August 2021, Gillig received a report from a separate customer with low floor buses that use a different type of rear chassis mounted ultracapacitor (KBI model) stating that it was possible to start the bus with the master battery disconnect switch in the OFF position.  Gillig began to investigate this customer’s report and in an abundance of caution disabled the ultracapacitor start feature in all buses at this customer’s location.  Notably, neither customer described the circumstances in which they observed that the engine could be started and neither reported that the engine had actually been started when personnel were present in the vicinity of the engine compartment.

 

In early to mid-September 2021, all 2020 and 2021 model year subject buses at the first customer received a software update to open and de-energize the ultracapacitor contactors when the battery disconnect switch is in the off position.  Subsequently the 2014-2019 buses were also updated.

 

In April 2022, Gillig received a communication from NHTSA advising that the first customer had submitted a complaint to the agency about the performance of the ultracapacitor system and alleging that the buses could be started even though the battery disconnect switch was in the “disconnected” position and claimed that this condition created a safety concern.  Gillig reviewed this communication and the customer’s allegation and the following day the customer confirmed to Gillig that all of its affected buses had already received the software update prior to submitting its report to NHTSA.   Gillig continued to review and consider the design of the ultracapacitor on the subject buses, particularly in light of the redundant series of instructions and practices that personnel are supposed to take in order to prevent the bus engine from being started during maintenance.

 

On April 22, 2022, notwithstanding the other redundant precautions, each of which entirely preclude the safety risk addressed in this petition, Gillig decided to conduct a safety recall out of an abundance of caution.  Gillig is not aware of any injuries that are potentially related to the condition.

 

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8 Affected Products

Vehicle

MAKE	MODEL	YEAR
GILLIG	LOW FLOOR	2014-2021

 

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8 Associated Documents

Miscellaneous Document- Chronology

RMISC-22V276-4320.pdf 98.106KB

 

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Defect Notice 573 Report

RCLRPT-22V276-1710.PDF 215.824KB

 

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Recall Acknowledgement

RCAK-22V276-4651.pdf 647.171KB

 

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Recall 573 Report- 06/08/2022

RCLRPT-22V276-5002.PDF 216.015KB

 

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Recall Quarterly Report #1, 2022-2

RCLQRT-22V276-8847.PDF 211.127KB

 

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Recall Quarterly Report #2, 2022-3

RCLQRT-22V276-8276.PDF 211.229KB

 

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Recall Quarterly Report #3, 2022-4

RCLQRT-22V276-1975.PDF 211.312KB

 

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Owner Notification Letter(Part 577)

RCONL-22V276-9341.pdf 94.714KB

 

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Latest Recalls Documents

https://www-odi.nhtsa.dot.gov/acms/cs/documentList.xhtml?docId=22V276&docType=RCL

 

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