What it means
The EPB module has detected an electrical fault in the clamp-force sensor circuit. Without this signal, regulated clamping force cannot be ensured and a fallback strategy is used.
How it works
The EPB module monitors the brake pressure sensor D circuit for the signal it uses to regulate clamping force. C0577 indicates that the circuit is open or has lost continuity, so the module cannot reliably confirm clamp force and may use a fallback strategy.
Common causes
Most likely first.
- Clamp-force sensor failed
- Wiring or connector fault
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
How to diagnose it
- Scan the EPB and brake systems for related codes and freeze-frame data, and check whether the module reports a missing sensor D signal or reduced-force fallback.
- Inspect the sensor D wiring and connector for a disconnected plug, damaged harness, corrosion, or a terminal pushed back into the connector.
- Check that the connector locks fully and that each terminal grips its mating pin, since a loose connection can interrupt the signal.
- Using the wiring diagram, test continuity through the sensor D circuit and check its supply and ground as specified by the manufacturer.
- If the circuit and connections are intact, test the clamp-force sensor against the manufacturer's specification before considering a module fault.
Common fixes
- Reconnect and secure the sensor D connector.
- Clean or repair corroded or loose connector terminals.
- Repair an open or damaged section of wiring.
- Replace the clamp-force sensor if it fails the manufacturer's tests.
- Repair or replace the EPB module only if sensor and circuit checks pass.
Can I keep driving?
Avoid relying on the parking brake's regulated clamping force until the fault is resolved, and park on level ground with the vehicle secured. If the ABS or stability-control warning is on or braking feels reduced, drive only as needed to reach a safe location and have the system inspected.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.