The OBD‑II code C0045 indicates a problem with the Brake Pressure Sensor B circuit. It means the vehicle’s system has detected a fault in the sensor that measures the pressure in the hydraulic brake line on the B side (typically the right side of the vehicle).
The sensor itself has failed or its internal circuitry is damaged, preventing accurate pressure readings.
Corrosion, broken wires, or a loose connector in the sensor circuit can interrupt signal transmission.
A leak or contamination in the hydraulic line can alter pressure readings or damage the sensor.
The ABS control module may misinterpret sensor data if it is defective.
A rare scenario where the vehicle’s engine computer misreads or misinterprets the sensor signal; typically last resort after other causes are ruled out.
In most cases, no. The code usually points to a sensor or wiring problem. Replacing the PCM is rarely necessary and should be considered only after all other causes have been ruled out.
No. Wiring faults, connector issues, brake fluid leaks, and ABS module problems can also trigger C0045. The sensor itself is the most common cause.
Once the root cause—typically the sensor or its wiring—is repaired, braking should return to normal. However, any underlying brake system issues must also be addressed to ensure safety.