Novak Conversions Jeep Wrangler JK engine mounts

Brake booster performance code after replacing booster

Cosmo5754

New Member
Joined
Apr 7, 2026
Messages
1
Location
Michigan
I recently replaced the power brake booster, brake booster vacuum sensor, brake light switch, and air pump. After completing this I did a brake flush and bled all of the calipers. I am still getting a stiff brake pedal and a C0021 code. After replacing the brake booster with a second new unit there was no improvement. While on the test drive after the second brake booster I got a U0414 code and the car started acting sluggish. Car seems to be in limp home mode and the transmission refused to let me shift it using the auto-stick, but I confirmed that the 4WD is still functional. After letting it sit for an hour that has gone away. I have replaced everything in the power braking system minus the master cylinder so I don't really know where to go from here. Thank you!

2014 Wrangler Unlimited Sahara 3.6
 
Novak Conversions Jeep Wrangler JK engine mounts