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.
Modulator Unit
The modulator unit consists of the inlet solenoid valve, the outlet solenoid valve, the VSA NO (normally open) solenoid valve, the VSA NC (normally closed) solenoid valve, the reservoir, the pump, the pump motor, and the damping chamber.
The hydraulic control has three modes at ABS action; pressure intensifying, pressure retaining, and pressure reducing. And pressure adding mode is combined at TCS, VSA, and brake assist action.
The hydraulic circuit is an independent four channel type; one channel for each wheel.
| Mode | VSA NO Valve | VSANC Valve | Inlet Solenoid Valve | Outlet Solenoid Valve | Brake Fluid | ||
|---|---|---|---|---|---|---|---|
| Pressure intensifying mode | open | closed | open | closed | Master cylinder fluid is pumped out to the caliper. | ||
| Pressure retaining mode | open | closed | closed | closed | Caliper fluid is retained by the inlet and outlet valves. | ||
| Pressure reducing mode | open | closed | closed | open |
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| Pressure adding mode | closed | open | open | closed |
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NO RELATED
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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.