Pre-purchase inspection checklist — 2021 Proterra Catalyst
The 2021 Proterra Catalyst presents noticeable issues, particularly with its electrical system and parking brake, both subject to recalls. Prospective buyers should be alert to these concerns, particularly during inspections and test drives.
Known issues to inspect
Radiator fan circuit overheating
How to check: Inspect the electrical system and software version; overheating signs.
Inverter overheating and failure
How to check: Check for software updates and inspect the inverter.
Wiper motor failure
How to check: Test wipers for consistent operation.
Parking brake engages unintentionally
How to check: Test the parking brake; listen for unexpected engagement.
Steering gearbox bolts loosen
How to check: Check for loose bolts or unusual noises during steering.
Test-drive walkthrough
- 01
Cold start
What to check: Check dashboard for electrical warning lights.
Red flag: Persistent warning lights
- 02
First minute idling
What to check: Listen for unusual radiator fan noises.
Red flag: Loud or inconsistent noise
- 03
Low-speed turns
What to check: Test steering responsiveness and noise.
Red flag: Steering wheel noise or play
- 04
Highway acceleration
What to check: Ensure consistent power steering with no noise.
Red flag: Loss of power steering
- 05
Windshield wiper use
What to check: Test if wipers operate smoothly and continuously.
Red flag: Wipers fail to operate
- 06
Parking brake check
What to check: Engage and disengage brake for smooth operation.
Red flag: Brake engages while driving
Questions for the seller
Use this exact phrasing.
- Has the inverter issue been addressed?
- Are there any outstanding recalls?
- Has the radiator fan software been checked?
- Have wiper motors been replaced?
- Is the parking brake operating correctly?
Documents to request
Don't sign anything until you have these.
- Recall repair records
- Service history
- Warranty documentation
- Software update logs
- Safety inspection report
Generated by gpt-4o on 8/24/2026. Grounded in the NHTSA recall corpus and owner-complaint patterns for the 2021 Proterra Catalyst.