Mikerson

The C101C code is a brake code and the corresponding OBD code is P258B. I found this document relevant: https://www.obd2-code.com/2017/08/p258b-electronic-vacuum-pump-performance.html

Hi Folks, I am here to find some help for my wife's car. It's a 2015 Hybrid SE. ~54K miles. Recently we got a "check brake system" warning on the dash. No drive-ability issues. No hard nor squishy brake pedal. I had the brake system codes read at Les Schwab. They stated that is has three brake codes. Below is what the printout says. C101C-01, BRAKE VACUUM PUMP (ELECTRICAL FAILURE) U3003-16, CIRCUIT VOLTAGE BELOW THRESHHOLD C1014-07, MECHANICAL FAILURE This sure sounds like it's a bad electrical vacuum pump to me. The pump has always been noisy. I complained to the dealership while it was still under warranty but they said it was normal. The pump seems to have gotten louder recently (though this could just be psychosomatic). Does anybody know how to diagnose this? I read somewhere (I'll post if I can find it) that it could also be a be a leaky brake booster, which causes low vacuum. I have done a few of the pedal height tests, but don't seem to notice issues with the booster. Thanks