C0570 indicates that the voltage signal from the brake booster travel sensor is above the expected range. The sensor tracks the position or travel of the brake booster diaphragm or push rod to help regulate brake assist. A circuit-high reading usually results from an electrical fault such as a short to power or a failed sensor, rather than a true mechanical over-travel condition.
The sensor's internal circuitry can fail and lock the output signal near supply voltage, causing a persistent high reading even when the booster is at rest.
A rubbed-through or melted wire can contact a voltage source, forcing the sensor signal line high independent of actual booster position.
Moisture, bent pins, or poor contact at the sensor or harness connector can create abnormal resistance and raise the circuit voltage beyond the calibrated threshold.
Binding, a broken return spring, or diaphragm damage can hold the sensor in a physical position that generates a voltage above the valid operating window.
In rare cases, an internal fault in the receiving module's analog input can misread a normal sensor signal as high, but this should only be considered after wiring and sensor faults are eliminated.
Short trips may be possible, but brake assist or electronic stability functions may be degraded; the issue should be diagnosed soon to ensure safe braking performance.
No. The control module is rarely the actual cause; most instances are resolved by repairing the sensor, wiring, or connector. Module replacement is usually unnecessary and should be a last-step diagnosis.
A vacuum leak affects assist level but does not typically raise the sensor circuit voltage; this code is primarily electrical, so focus on the sensor and wiring first.
A signal wire shorted to a power source or an internally shorted sensor will pull the circuit to system voltage, which the module interprets as a circuit high fault.