Normal Operation and Fault Conditions

The brake booster vacuum 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 0.2 volt and 4.9 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.

PPT C ABS MODULE DTC FAULT TRIGGER CONDITIONS

DTC	Description	Fault Trigger Conditions
C0047:01	Brake Booster Pressure Sensor: General Electrical Failure	Sets when the ABS module detects the signal returned by the sensor is above or below a predetermined limit. This is usually caused by a short to voltage, an open or an internal failure of the sensor.
C0047:1B	Brake Booster Pressure Sensor: Circuit Resistance Above Threshold	Sets when the ABS module detects higher resistance than expected 3 times, a failure counter is increased by 1. If the failure counter reaches 10, this DTC is set. This is usually caused by higher than normal resistance in the circuits or an internal failure of the sensor.
C0047:26	Brake Booster Pressure Sensor: Signal Rate of Change Below Threshold	Sets when the ABS module detects the rate of change in the signal transmitted by the vacuum sensor does not match a predetermined threshold depending on the brake system pressure, or if a characteristic oscillation in the vacuum signal is not detected. A signal failure is reported when 3 valid braking cycles, within the same ignition cycle, have met the above criteria. This is usually caused by a failure in the sensor circuits, a vacuum leak in the brake booster, a mechanical failure of the brake booster or an internal failure of the vacuum sensor.
C0047:27	Brake Booster Pressure Sensor: Signal Rate of Change Above Threshold	Sets when the ABS module detects the rate of change in the signal transmitted by the vacuum sensor increases beyond a predetermined level when the brakes are not being applied. When this condition is detected, the ABS module starts a counter and monitors the rate of change, if the rate of change increases beyond the limit 3 times during this time period, this DTC sets. This is usually caused by a failure in the sensor circuits or an internal failure of the sensor.
C1015:08	Vacuum Supply: Bus Signal/Message Failure	As long as the sensor is powered, it must send a data frame every 3 milliseconds. Sets when the ABS module does not receive at least 1 data transfer within the specified time.
C1B14:11	Sensor Supply Voltage "A": Circuit Short to Ground	Sets when the ABS module detects a short to ground on the voltage supply circuit to the brake booster vacuum sensor.
C1B14:12	Sensor Supply Voltage "A": Circuit Short to Battery	Sets when the ABS module detects a short to battery voltage on the voltage supply circuit to the brake booster vacuum sensor.
C1B15:1C	Sensor Supply Voltage "B": Circuit Voltage Out of Range	Sets when the ABS module detects the output voltage to the brake booster vacuum sensor is either above or below the specified voltage for a predetermined amount of time.