Normal Operation and Fault Conditions

WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

The brake booster vacuum pressure sensor receives a sensor supply voltage of 5 volts from the ABS module. The sensor is also grounded through the ABS module. The sensor uses the pressure differential between the atmosphere and the brake booster vacuum chamber to produce a return voltage signal to the ABS module between 0.39 volt and 4.38 volts. The ABS module uses other sensor inputs such as wheel speed, brake pedal and stability sensors to determine if the vehicle is stopping and at what rate of deceleration. This information is compared against the vacuum pressure sensor to determine the validity of the sensor signal and the working condition of the sensor itself. An open circuit, a short to ground, a short to voltage or a faulted vacuum sensor cause the ABS module to set a DTC.

PPT CA ABS MODULE DTC FAULT TRIGGER CONDITIONS

DTC	Description	Fault Trigger Conditions
C101A:15	Vacuum Pressure Sensor: Circuit Short To Battery or Open	This DTC sets in continuous memory in the ABS module if the brake booster vacuum sensor return signal line outside the expected range, 0.3 volt and 4.7 volts.
C101A:16	Vacuum Pressure Sensor: Circuit Voltage Below Threshold	This DTC sets in continuous memory in the ABS module if the brake booster vacuum sensor return signal line outside the expected range, 0.3 volt and 4.7 volts.
C101A:1C	Vacuum Pressure Sensor: Circuit Voltage Out of Range	This DTC sets in continuous memory if the 5-volt sensor supply voltage falls outside of a predetermined specification (either too high or too low).
C101A:29	Vacuum Pressure Sensor: Signal Invalid	This DTC sets in continuous memory in the ABS module if the driver applies the brake pedal and the brake fluid pressure sensor indicates an increase in pressure but the vacuum level in the brake booster does not decrease by the expected amount.