2013 Hyundai Sonata Hybrid Limited – Brake Pump Runs Continuously With C1237
- Aug 16
- 1 min read
CUSTOMER CONCERN
A motor-like noise runs continuously under the hood and the Active Hydraulic Booster stores DTC C1237 for the primary pressure-sensor signal.
CAUSE
Hydraulic pressure data did not respond while HPU battery feeds at pins 1, 2, and 3 and grounds at pins 25 and 26 were present, confirming an internal Hydraulic Power Unit failure.
CORRECTION
Remove and replace the failed Hydraulic Power Unit, bleed the brake system, perform pressure-sensor calibration and required relearns, clear DTC C1237, and road test to verify brake-assist operation.