Less than 2 weeks after picking up our brand new 2021 Model Y LR, we experienced a scary partial brake failure in the middle of driving. Symptom was the brake pedal becoming very stiff; it took great leg strength to press down the pedal to have some braking effect. The orange brake warning light was on, as well as two alerts: IBST_a082 "Power braking assist reduced" and DI_a245 "Vehicle Hold feature unavailable".
We pulled over and looked up what these errors mean. According to the owner's manual it seems the "brake booster" has failed, but the backup hydraulic boost compensator can still function, providing some amount of brake assist. Fortuantely we were on a local road not far from home, and regen braking was working fine, so we decided to cautiously drive home (and we made it to home safely). But what a strange and scary experience! Who would've expect a brand new car to have brake failures? What if this happened when we were driving 70+mph on a highway and needed to emergency brake??
Both errors went away after leaving the car for a while (effectively power cycled). But I am unwilling to believe it was a software glitch. If it happened once, it could happen again (perhaps even on the highway). I scheduled an appointment with my nearest SC for next week. Got a message within the same day saying I could brought the car in any time during business hours since this is a safety issue. The service advisor also said I could have the car towed to SC if I felt unsafe driving it. Brought the car in the morning after (days ahead of my appointment slot), SC immediately took the car in and started diagnostics. Around noon I got a call from the service advisor saying they looked the logs and it is very likely the brake booster is faulty, so they are going to replace the entire brake booster assembly:
Service provided by the Fremont SC has been really great. At least they are willing to replace the faulty part instead of telling me to just "power cycle the car and it'll be ok". But c'mon Tesla. I can tolerate cosmetic defects like misaligned panels and gaps. But defects in a safety-critical component in a brand new car?? That's too much. They really need to step up their quality control, be it IQC or OQC.
Also, I recommend all Model Y owners to closely study the "Braking Systems" section in the owners manual (page 60). Make sure you are prepared to exert enough leg force to brake in case the brake booster fails. Also know that you could press and hold the P button on the drive stalk to engage emergency braking in dire situation. Only use this if absolutely necessary.
Hope this doesn't happen to anyone else.
Cheers.
We pulled over and looked up what these errors mean. According to the owner's manual it seems the "brake booster" has failed, but the backup hydraulic boost compensator can still function, providing some amount of brake assist. Fortuantely we were on a local road not far from home, and regen braking was working fine, so we decided to cautiously drive home (and we made it to home safely). But what a strange and scary experience! Who would've expect a brand new car to have brake failures? What if this happened when we were driving 70+mph on a highway and needed to emergency brake??
Both errors went away after leaving the car for a while (effectively power cycled). But I am unwilling to believe it was a software glitch. If it happened once, it could happen again (perhaps even on the highway). I scheduled an appointment with my nearest SC for next week. Got a message within the same day saying I could brought the car in any time during business hours since this is a safety issue. The service advisor also said I could have the car towed to SC if I felt unsafe driving it. Brought the car in the morning after (days ahead of my appointment slot), SC immediately took the car in and started diagnostics. Around noon I got a call from the service advisor saying they looked the logs and it is very likely the brake booster is faulty, so they are going to replace the entire brake booster assembly:
Service provided by the Fremont SC has been really great. At least they are willing to replace the faulty part instead of telling me to just "power cycle the car and it'll be ok". But c'mon Tesla. I can tolerate cosmetic defects like misaligned panels and gaps. But defects in a safety-critical component in a brand new car?? That's too much. They really need to step up their quality control, be it IQC or OQC.
Also, I recommend all Model Y owners to closely study the "Braking Systems" section in the owners manual (page 60). Make sure you are prepared to exert enough leg force to brake in case the brake booster fails. Also know that you could press and hold the P button on the drive stalk to engage emergency braking in dire situation. Only use this if absolutely necessary.
Hope this doesn't happen to anyone else.
Cheers.
