Brake pressure sensor B signal voltage below expected range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
High severity. Can I keep driving?The regular brakes usually keep working, but without ABS or the driver aids. Drive very carefully and go to a repair shop; if the pedal feel changes, do not keep driving.
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Most likely causes
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
What each character of C0542 means
- C: Chassis
- 0: Generic code: same on every make
- 5: Subsystem depends on the code range
- 42: Specific fault in that system
Frequently asked questions
Can I keep driving with code C0542?
The regular brakes usually keep working, but without ABS or the driver aids. Drive very carefully and go to a repair shop; if the pedal feel changes, do not keep driving.
What causes code C0542?
The most common causes are: signal wire shorted to ground; connector pins corroded - high contact resistance; harness chafing through insulation.
Related codes
- C053EBrake Pressure Sensor A Circuit Low
- C059FBrake Pressure Sensor E Circuit Low
- C05C6Brake Pressure Sensor F Circuit Low
- C0637Brake Pressure Sensor G Circuit Low
- C063BBrake Pressure Sensor H Circuit Low
- C063FBrake Pressure Sensor J Circuit Low
- C0643Brake Pressure Sensor K Circuit Low
- C0647Brake Pressure Sensor L Circuit Low
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.