P24BBEVAP System Leak Detection Pump Pressure Sensor Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P24BB is stored when the leak check module's pressure signal climbs above the top of its usable range. GM uses 4.85 V, about 97 % of the reference or roughly 120 kPa, again with 640 of 800 samples and Type B; the limit appears unchanged from the 2018 Volt up to GM's 2025 table 25OBDG03A for conventional ELCP systems. Mitsubishi's 2023 Outlander PHEV flags the code above 4.9 V lasting 2 s. Subaru lists P24BB with P24BA and P24B9 as faults to clear first when P2404 appears. A reading pinned high usually comes from an open ground, a signal wire touching a voltage source or an internal sensor fault, rarely from real pressure. P24BA covers the low side; P24B9 a signal that stays in range but disagrees with barometric pressure.
- What you may notice
- Malfunction indicator lamp on
- EVAP leak test not run, readiness incomplete
- Likely causes
- LikelyOpen sensor ground or signal wire, letting the input float high
- PossibleSignal wire shorted to the 5 V reference or battery voltage
- PossiblePressure sensor inside the leak check module failed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €50 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.