Normal Operation

The brake pressure transducer is integral to the Hydraulic Control Unit (HCU). The transducer sends a signal to the ABS module that varies in relation to the amount of pressure applied to the brake pedal. The more pressure that is applied, the greater the signal sent to the ABS module. If a new transducer needs to be installed, then a new HCU must be installed.

• DTC C1288 (Pressure Transducer Main/Primary Input Circuit Failure) - If the transducer is open, shorted to ground or shorted to voltage, DTC C1288 will be set.
• DTC C1440 (Pressure Transducer Main/Primary Signal Faulted) - The signal that the brake pressure transducer sends to the ABS module is checked against other inputs to the module and if it does not agree with those inputs, DTC C1440 is set.
• DTC C1446 (BOO (Brake ON/OFF) Plausibility Fault(s)) - During normal operation, the ABS module compares the brake ON/OFF High Speed Controller Area Network (HS-CAN) message to the HCU internal pressure transducer. If the brake ON/OFF message does not match the HCU transducer, DTC C1446 will be set.

This pinpoint test is intended to diagnose the following:

• HCU
• ABS module