Boost Pressure Fault (Non-Latching)

BOOST PRESSURE FAULT (NON-LATCHING)

WARNING LIGHTS
BRAKE and ANTILOCK, during a brake application.

DETECTION
This fault is detected anytime during a brake application.

DESCRIPTION
This is a fault in the hydraulic boost pressure system.

The boost pressure transducer senses boost servo pressure and converts it to voltage on a 0.25 - 5.0 volt linear scale; i.e., 0.25 volts equals 0 psi, and 5.0 volts equals 2500 psi. This voltage is compared to the output of the primary pressure transducer to determine proper operation.

- Boost pressure and primary pressure should always be approximately equal.
- Boost pressure typically will be higher than primary pressure by a few hundredths of a volt because of friction losses in the piston seals in the master cylinder.
- If boost pressure is below 300 psi of primary pressure, then the BOOST PRESSURE fault is set.