Normal Operation
The pressure transducer is integral to the Hydraulic Control Unit (HCU). The pressure 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 is applied, the greater the signal sent to the ABS module. If a new pressure transducer is needed, then a new HCU must be installed.
When the brake pedal is pressed, the stoplamp switch closes and voltage is sent to the PCM. The PCM then sends a message over the High Speed Controller Area Network (HS-CAN) to the ABS module indicating the brake pedal has been pressed. DTCs set in the ignition cycle can only be cleared by cycling the ignition off and on once the fault has been corrected.
- DTC C116A (ABS Pressure Transducer/Brake Switch Mismatch) - this DTC sets in every ignition cycle if, during normal operation, the stoplamp switch message does not match the HCU transducer, both signals have to agree about whether the brakes are being applied or not.
- DTC C1440 (Pressure Transducer Main/Primary Signal Faulted) - this DTC sets in every ignition cycle if the signal the pressure transducer sends to the ABS module does not agree with the stoplamp switch position.
This pinpoint test is intended to diagnose the following:
- Network communication concern
- Stoplamp switch
- HCU