Recall 22V855 affects 386 2019-2022 Proterra ZX5 and Catalyst transit buses for unintended parking-brake engagement. Proterra will install the redesigned air circuit for free.
Proterra is recalling 386 2019-2022 ZX5 and Catalyst transit buses because back pressure in a shared air exhaust can engage the parking brake while the bus is moving. Unintentional parking brake engagement increases crash risk, and Proterra dealers will complete the recall repair free of charge.
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What's wrong?
On 2019-2022 Proterra ZX5 and Catalyst buses, the pneumatic system uses air pressure to control ride height and the parking brake. Ride height air raises or lowers the bus suspension, while the parking brake control valve at the driver console applies or releases the brake. A check valve is supposed to keep air moving in the intended direction.
On affected buses, the ride height system and parking brake control valve share an exhaust path. Back pressure from the ride height exhaust can bleed past the check valve and reach the exhaust outlet of the parking brake control valve. Under the wrong system condition, that pressure can apply the parking brake while the bus is moving.
There is no warning sign before failure. A driver is not given a specific light, sound, or pedal feel to rely on before the parking brake applies. If this happens, the practical clue is the brake engaging unexpectedly during driving, which means the bus needs Proterra service before it returns to normal use.
Who's affected?
Covers both ZX5 and Catalyst buses across 2019-2022, all tied to the same parking brake air valve subassembly.
| 2020 Proterra ZX5 | Parking brake |
|---|---|
| 2022 Proterra ZX5 | Parking brake |
| 2021 Proterra ZX5 | Parking brake |
| 2021 Proterra Catalyst | Parking brake |
| 2020 Proterra Catalyst | Parking brake |
| 2019 Proterra ZX5 | Parking brake |
| Units affected | 386 |
| Field incidents | NHTSA has logged no field incidents to date. |
The year and model narrow the scope, but the VIN decides. Check your VIN to confirm whether your specific bus is included.
What's the safety risk?
If the parking brake engages without command, the vehicle can slow or stop unexpectedly and increase the risk of a crash. Treat any unexpected brake engagement as a reason to pull over safely and contact Proterra service. Repair is free at any franchised Proterra dealer.
What should I do?
- Check your VIN to confirm your 2019-2022 Proterra ZX5 or Catalyst bus is included in this recall.
- Contact a franchised Proterra dealer to schedule the free redesigned air-circuit repair that addresses shared exhaust back pressure that can engage the parking brake while the bus is moving.
- Bring the recall notice if Proterra mailed one. If not, reference recall number 22V855 when you call.
- Keep drivers alert for unexpected parking brake engagement until the repair is complete, and remove the bus from service if it happens.
- Call Proterra customer service at 1-864-438-0000 with questions about scheduling or repair status.
What happens at the repair
At the dealer, a Proterra technician installs a redesigned air circuit for the shared air exhaust used by the pneumatic ride height system and parking brake control valve. The recall repair is free, and parts and labor are covered. Proterra's General Reimbursement Plan covers affected owners who already paid for a related repair before the recall notice. Bring repair invoices, receipts, or other service documentation to Proterra customer service or the dealer so the claim can be reviewed under that plan.
| Reimbursement | Reimbursement available |
|---|
Timeline
| November 18, 2022 | NHTSA published the recall |
|---|---|
| December 12, 2022 | Dealer notification began |
| December 12, 2022 | Interim owner notification (was planned for this date) |
| December 21, 2022 | Owner notification mailed |
| January 17, 2023 | Dealer notification ended |
| January 17, 2023 | VIN-searchable in NHTSA's database — Check your VIN to see whether this recall applies to your specific vehicle. |
Frequently asked questions
What is recall 22V855?
Recall 22V855 covers 386 2019-2022 Proterra ZX5 and Catalyst transit buses. Back pressure in the shared air exhaust for the pneumatic ride height system and parking brake control valve can engage the parking brake while the bus is moving. Proterra will install a redesigned air circuit for free.
What should I do if my 2019-2022 Proterra ZX5 or Catalyst is on this recall?
Check your VIN to confirm whether your specific bus is included in recall 22V855. If it is, contact Proterra service or an authorized Proterra service location and ask for the redesigned air circuit installation. Reference recall number 22V855 when you call. The repair is free.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost, and Proterra will install the redesigned air circuit free of charge. Parts and labor are covered for included 2019-2022 Proterra ZX5 and Catalyst buses.
What is the safety risk?
The safety risk is unintentional parking brake engagement while the bus is in motion. NHTSA campaign 22V855 says that condition increases the risk of a crash. The repair path is the redesigned air circuit that Proterra installs for free.
When were owners notified about recall 22V855?
Proterra mailed owner notification letters on December 21, 2022. If your fleet did not receive a letter, the VIN still decides whether the bus is included. Check your VIN, then contact Proterra service at 1-864-438-0000 with recall number 22V855.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/22V855000 |
|---|---|
| Proterra customer service | 1-864-438-0000 |
| NHTSA recall # | 22V855 |
| NHTSA recall # (full) | 22V855000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Quarterly Report (PDF)
- Download Recall Report (PDF)
- Download Owner Notification Letter (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 20, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →