C0645Brake Pressure Sensor L Circuit/Open
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- ESC and ABS warning lamps on
- Pressure-based functions such as brake assist or hill hold unavailable
- Likely causes
- LikelySpring contact between sensor and module board bent, dirty or corroded
- PossiblePlug or harness of an externally mounted sensor without continuity
- RareInternal interruption in sensor L
- Repair
- Hard · Usually a job for a workshop.Typical cost: €60 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.