Code Description

Pressure Transducer Main/Primary Input Circuit Failure

The ABS module monitors the brake pressure transducer in combination with other brake inputs: wheel speed sensors, stoplamp switch from the PCM over the High Speed Controller Area Network (HS-CAN) bus and lateral accelerometer from the sensor cluster. The pressure transducer signal is used by the ABS module for various diagnostic routines as well as to determine system functionality. The pressure transducer is located inside the Hydraulic Control Unit (HCU) and can be monitored via the master cylinder pressure (MC_PRESS) PID. The PID should correlate closely with system hydraulic pressure. When the vehicle is at rest without input from the brake pedal, this PID value should be at or close to 0 kPa (0 psi). However, due to factors such as vehicle age or minor discrepancies in manufacturing, PID readings may have some variability. If the transducer requires service, a new HCU must be installed.

Possible Causes

• DTC C1288 (Pressure Transducer Main/Primary Input Circuit Failure) - If during the ABS module self-test or normal operation a condition (such as a short or open circuit) occurs that causes the transducer signal to read above 1,710 kPa (248 psi) when other inputs indicate a non-pressurized system, DTC C1288 will be set.