What it means
Same as P24B8 with the signal voltage below the plausible range. The evaporative system captures fuel vapor from the tank and purges it into intake; leaks or stuck purge valves leak hydrocarbons and cause emissions failures.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The leak detection pump checks the evaporative vapor system by creating pressure or vacuum, while its pressure sensor reports the result to the control module. This code sets when the sensor signal falls below the plausible range, which can happen if the signal is shorted to ground or the circuit has a poor connection.
Common causes
Most likely first.
- Signal shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
How to diagnose it
- Record freeze-frame data and check for other evaporative codes that may help identify a broader pump or wiring issue.
- Inspect the leak detection pump pressure sensor connector and harness for corrosion, moisture, loose pins, and chafing to ground.
- Check the pressure-sensing hose for a leak, restriction, or disconnection that could accompany the circuit fault.
- Use live data to confirm whether the pressure signal remains low during the manufacturer's specified pump test.
- Test the sensor signal wire for a short to ground and check the sensor and pump circuit using the manufacturer's wiring information.
Common fixes
- Repair chafed pressure sensor wiring shorted to ground.
- Clean and secure corroded or loose connector terminals.
- Reconnect or replace a damaged pressure-sensing hose if inspection finds a leak or blockage.
- Replace the pressure sensor or pump if circuit testing confirms that component has failed.
Can I keep driving?
Driving is usually possible if the vehicle behaves normally, but take a fuel-vapor smell seriously and keep ignition sources away from the area. The low signal can disable evaporative leak checks and lead to an emissions inspection failure.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.