Code C0543 indicates that the brake pressure sensor designated "B" is reporting a voltage signal higher than the expected range. This condition is detected by the brake control module or the vehicle's main computer and typically points to a sensor or wiring issue rather than a computer failure.
The sensor itself may have an internal short or drift causing an excessively high output voltage.
Damaged insulation, a broken wire, or a short to power in the sensor circuit can raise the measured voltage.
Oxidation or poor contact at the sensor connector can create a high‑resistance path that the module interprets as a high signal.
An internal driver or reference voltage problem in the module can cause it to read the sensor circuit as high.
A defective main computer could misinterpret the sensor signal, but this is only considered after all sensor and wiring checks are normal.
No. The PCM is rarely the cause; the fault is almost always the sensor, its wiring, or the brake control module.
Driving is not recommended because the brake system may not provide proper assist or ABS functionality.
Use a scan tool to erase the code once the underlying issue has been corrected and the system passes a self‑test.
They are separate sensors monitoring different hydraulic circuits; each has its own wiring and calibration.