What it means
The exhaust aftertreatment fuel-air purge valve control circuit signal is above the expected range. The code does not by itself identify the cause or valve state.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The exhaust aftertreatment fuel-air purge valve is operated through a control circuit that the module monitors. P24FB means the circuit signal is higher than expected, which can occur with a control wire shorted to battery voltage, an open ground or coil, or a high-resistance connection.
Common causes
Most likely first.
- Control wire shorted to battery voltage
- Open ground or open coil
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- Aftertreatment warning light
- Reduced engine power or performance
- Increased exhaust emissions
How to diagnose it
- Save freeze-frame data and check for related charging or dosing-module voltage codes that could affect the circuit reading.
- Inspect the purge-valve wiring and connector for damage, corrosion, loose pins, or contact with a power feed.
- With the circuit isolated according to the manufacturer's procedure, check the control wire for a short to battery voltage.
- Check valve-coil continuity and ground-path integrity against the manufacturer's specification.
- If wiring and coil tests pass, run the approved output test to determine whether the dosing module is reporting or driving the circuit incorrectly.
Common fixes
- Clean and secure corroded or loose circuit terminals.
- Repair the control wire if it is shorted to battery voltage.
- Repair an open ground or replace a valve with an open coil.
- Repair or replace the dosing module if its circuit output is confirmed faulty.
Can I keep driving?
Keep driving limited and avoid heavy loads because purge control and exhaust emissions may be affected. Follow any warning that calls for reduced speed or stopping.
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.