C0045 code meaning
Brake Pressure Sensor B
What C0045 means
C0045 covers brake pressure sensor B, the second pressure transducer in the ABS/ESC hydraulic unit next to sensor A (C0044). Two sensors let the module watch both brake circuits or check one reading against the other for stability control, brake assist and brake-by-wire functions. The code sets for a signal out of range, an open or short, or a value that disagrees with sensor A or the pedal demand. Where the sensor sits inside an integrated brake unit, repair usually means replacing the whole unit. NHTSA's EPS safety report lists C0045 with this J2012 meaning. Older GM vehicles use C0045 for the left rear wheel speed sensor circuit instead (GM PIE0456, 16-NA-248), so the make decides what a stored C0045 means.
C0045 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0045
- ABS or brake warning lamp on
- Stability and assist functions disabled
- Changed brake assist behaviour
Common causes of C0045
- Most likelyPressure sensor failed or out of range
- PossibleFault internal to the integrated brake unit
- Less likelySignal does not correlate with sensor A
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake pressure sensor b
What each part of C0045 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 45 | The exact fault in that area. |
What to do next
- Note C0045 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 C0045
What does C0045 mean?
C0045 means "Brake Pressure Sensor B". C0045 covers brake pressure sensor B, the second pressure transducer in the ABS/ESC hydraulic unit next to sensor A (C0044). It is a generic code, so it means the same on every make.
Is it safe to drive with C0045?
Drive gently and only to a workshop. With C0045 the car can go into limp mode (reduced power) to protect itself.
Will C0045 fail an emissions test?
C0045 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 C0045 to fix?
Difficulty: workshop only. A typical repair takes 1.5 to 4 hours of work. This is a job for a workshop.
Will C0045 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.