C0645 code meaning
Brake Pressure Sensor L Circuit/Open
What C0645 means
C0645 reports lost continuity in the circuit of brake pressure sensor L, the eleventh letter of the series because I is not used. That is far beyond a normal car: a Bosch patent names one, three or five sensors as the usual ESP layouts and calls five the current maximum. No carmaker publishes which sensor would carry the L. Where it does exist, the sensor is often clinched straight into the valve block, and Continental and Bosch both describe its four contacts (supply, ground, two signal pads) touching spring contacts on the module board instead of a harness. An open is then frequently a bent spring, a corroded pad or a crack inside the unit, not a broken wire. Expect the ESC and ABS lamps; ordinary braking is kept.
C0645 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0645
- ESC and ABS warning lamps on
- Pressure-based functions such as brake assist or hill hold unavailable
Common causes of C0645
- Most likelySpring contact between sensor and module board bent, dirty or corroded
- PossiblePlug or harness of an externally mounted sensor without continuity
- Less likelyInternal interruption in sensor L
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake pressure sensor lSensor wiring
What each part of C0645 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 C0645 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 C0645
What does C0645 mean?
C0645 means "Brake Pressure Sensor L Circuit/Open". C0645 reports lost continuity in the circuit of brake pressure sensor L, the eleventh letter of the series because I is not used. It is a generic code, so it means the same on every make.
Is it safe to drive with C0645?
Drive gently and only to a workshop. With C0645 the car can go into limp mode (reduced power) to protect itself.
Will C0645 fail an emissions test?
C0645 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 C0645 to fix?
Difficulty: hard. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will C0645 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.