C0542 code meaning
Brake Pressure Sensor B Circuit Low
Chassis system Generic code C05xx codes Check engine light
What C0542 means
Brake pressure sensor B pulls its signal below the lowest voltage the receiving module treats as valid. Two makers name the code in public bulletins. Bentley lists C054200 in the ESC unit J104 of the Continental GT/GTC and Flying Spur alongside C054100, with adaptive cruise switched off and the J104 replaced. Stellantis lists C0542 as Brake Pressure Sensor 2 Circuit Low among powertrain-module faults of the 2019 Jeep Cherokee with 3.2-litre V6 and engine stop-start; there a PCM software update was the remedy, with a check-engine lamp as the complaint. As a reference for the electrical limit, a Saab 9-5 brake unit treats anything under 0.25 V lasting 0.1 s as a sensor fault. Signal shorts to ground, a missing 5-V feed or a failed sensor are the usual causes.
C0542 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.3 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0542
- Check-engine or ESC warning lamp on
- Adaptive cruise control or stop-start unavailable
Common causes of C0542
- Most likelySignal line shorted to ground
- PossibleSensor or the ESC unit with integrated sensor defective
- PossibleEngine control software misjudging the signal (Jeep Cherokee 2019)
- Less likely5-V sensor supply dragged down
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake pressure sensor bSensor wiring
What each part of C0542 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 42 | The exact fault in that area. |
What to do next
- Note C0542 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C0542
What does C0542 mean?
C0542 means "Brake Pressure Sensor B Circuit Low". Brake pressure sensor B pulls its signal below the lowest voltage the receiving module treats as valid. It is a generic code, so it means the same on every make.
Is it safe to drive with C0542?
Drive gently and only to a workshop. With C0542 the car can go into limp mode (reduced power) to protect itself.
Will C0542 fail an emissions test?
C0542 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C0542 to fix?
Difficulty: medium. A typical repair takes 0.3 to 3 hours of work. This is a job for a workshop.
Will C0542 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.