P24D6 code meaning
EVAP System Pressure Sensor/Switch B Circuit Range/Performance
Powertrain system Generic code P24xx codes Check engine light
What P24D6 means
P24D6 is a plausibility fault of EVAP pressure sensor B. GM's 2023 table 23OBDG03A checks the canister vapour pressure sensor at the start of a cold drive: after more than 3,600 s soak the offset must sit within a window around barometric pressure; a filtered ratio above 0.73 sets the code, Type A. GM bulletins 24-NA-162 and 24-NA-258 trace P24D6 on 2024–2025 Silverado and Sierra HD 6.6L trucks to a narrow-range sensor fitted at the plant (about 1.5 V instead of 2.625 V at rest). Mitsubishi's 2023 Outlander PHEV compares tank, differential and canister pressures for 180 s during the engine-off test. Audi lists it for V6/V8 sensor G950, FCA for 2017–2018 Giulia software. P24D7/P24D8 are hard voltage limits.
P24D6 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P24D6
- Malfunction indicator lamp on
- Other EVAP codes such as a switching valve fault may appear alongside
- No driveability change
Common causes of P24D6
- Most likelyWrong sensor version installed (GM HD trucks, narrow-range instead of wide-range)
- PossibleSensor offset drifted away from barometric pressure
- PossibleKinked hose or blocked port at the sensor
- Less likelyEngine control software needing an update (FCA, Audi)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EVAP pressure sensor b
What each part of P24D6 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| D6 | The exact fault in that area. |
What to do next
- Note P24D6 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 P24D6
What does P24D6 mean?
P24D6 means "EVAP System Pressure Sensor/Switch B Circuit Range/Performance". P24D6 is a plausibility fault of EVAP pressure sensor B. It is a generic code, so it means the same on every make.
Is it safe to drive with P24D6?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P24D6 fail an emissions test?
Yes, it can. P24D6 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P24D6 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P24D6 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.