What it means
Same as P24C0 with the valve stuck off. 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 switching valve directs pump flow between EVAP test paths under control-module command. P24C1 sets when the valve fails to activate when commanded, or its response indicates it is stuck off, preventing the expected leak-test routing.
Common causes
Most likely first.
- Valve stuck off
- Carbon or debris buildup preventing free movement
- Component wear with age - mechanical play
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
- Save freeze-frame data and check live valve-command and EVAP pressure data to confirm the conditions when the valve was expected to activate.
- Inspect the switching valve connector and harness for an open, loose pin, corrosion, or damaged wiring.
- Use a supported scan-tool output test to command the valve on and off and check whether the EVAP response changes as expected.
- Test the valve control circuit for opens, shorts, and poor connections using the wiring diagram and manufacturer's procedure.
- If the electrical command reaches the valve, inspect or test the valve for sticking or blockage according to vehicle service information.
Common fixes
- Repair an open or poor connection in the valve control wiring.
- Reseat or replace loose or corroded connector terminals.
- Free a sticking valve if the manufacturer's procedure permits cleaning or service.
- Replace the switching valve if it does not operate despite correct control signals.
Can I keep driving?
The vehicle will usually remain driveable, but the EVAP leak test may not complete and an emissions inspection may fail. Address a continuing fuel smell promptly.
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.