Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC C1234: High Pressure Accumulator Long Term Charge Error: General Description
There are three pressure sensors in HPU (Hydraulic Power Unit). They each measure high pressure accumulator pressure, booster pressure, pedal simulator pressure. IBAU (Integrated Brake Actuation Unit) uses these measured values to monitor AHB operating status and control AHB.
After replacing IBAU, pressure sensor calibration and PTS calibration are essential.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.